I think that your question makes flawed assumptions.
One) That every planet that has life must have intelligent life who count as people.
Two) That every planet that has intelligent life must have only one species of intelligent life who count as people.
The planet Earth proves that both assumptions are inaccurate.
One) Earth was occupied by only single celled life and viruses for billions of years. Eventually photosynthetic single celled organisms produced oxygen faster than oxidation could remove it from the atmosphere, and lifeforms evolved to tolerate oxygen and to use it. Oxygen using lifeforms developed multicellular organisms.
Assuming that single celled organisms couldn't possible be intelligent beings, and that many multicelled organisms likeplants and sponges couldn't possibly be intelligent beings, the first possibility of multicelled lifeforms advanced enough to be intelligent beings would have been about maybe 600 million years ago.
So Earth probably had lifeforms for billions of years before lifeforms which could possibly develop intelligence evolved.
By looking at a planet from afar and measuring its conditions with various instruments we can tell if the planet can possibly have intelligent life as we know it at the moment, not whether it does have intelligent life as we know it at the moment.
And an advanced technological civilization may cause environmental changes which can be detected at a distance. But advanced technological civilization has existed on Earth for only a few hundred or a few thousand years, while there have been intelligent beings of the genus Homo on Earth for hundeds of thousands or millions of years. Human civilization might exist for hundreds of thousands or millions of years in the future, but that would not change the hundreds of thousand or millions of years that intelligent life existed on Earth without making any signs which could be detected at a distance.
Two) The history of Earth shows that it is possible for a planet to have more than one species of intelligent life living on it at the same time.
Homo sapiens evolved about 300,000 yeas ago.
Homo floresiensis existed on Flores hundreds of thousands of years before becoming extic 60,000 or 50,000 years ago.
The Denisovan species or subspecies may have existed over 200,000 years ago and as recently as 50,000 years ago.
Homo neanderthalenis may have existed more than 400,000 yeas ago and became extinct about 40,000 years ago.
Homo erectus existed from about 2,000,000 years ago to about 100,000 years ago.
Homo habilis existed from about 2,310,000 years ago to about 1,650,000 years ago.
Members of various species in the genus Australopithicus existed from about 4,200,000 years ago to about 1,900,000 years ago or later. And members of Australopithicus may be considered by many persons to have been intelligent beings.
Most of the thousands of mammal species are small. There are hundreds of large mammals, large enough to suport large brains. And some of those large mammal species have evolved large brains for various reasons. And mammals with large brains may develop high intelligence, including intelligence ranges which greatly overlap with those of humans.
Two species of chimps and two species of gorillas may be intelligent enough to count as intelligent beings. Maybe the three species of orangutans and the 20 species of gibbons are also intelligent enough to count as intelligent beings.
The three species of elephants also may be intelligent enough to count as intelligent beings. And over fifteen species, if I counted correctly, of large brained proposcideans related more or less closely to modern elephants became extinct during the last 13,000 years or so. Fossil proboscideans with large brains have existed for at least 10 million years.
Cetacea is an infraorder that comprises the 94 species of whales, dolphins, and porpoises.
https://en.wikipedia.org/wiki/List_of_cetaceans
All cetacean species have large brains and many have been observed exhibiting high intelligence. Nobody can be certain whether none, some, or all, cetacean species should be considered to be intelligent beings. Large brained cetaceans have existed for at least 10 million years.
Thus it is possible that the planet Earth currently has between one and over one hundred species of intelligent mammals. And it possible that Earth has had at least two species of intelligent mammals at a time for over ten milions years and possibly much longer.
Most flying birds are quite small, and thus they have small brains. But bird brains seem to have evolved high efficiency in order to have sufficient functionality for survival in such small brains.
So some species of birds, such as parrots and corvids, seem to display high intelligence approachign that of humans, despite their entire bodies being not much heavier than human brains. Thus the idea of past, present, or future intelligent species of birds is fairly reasonable.
If other groups of flying creatures also develop highly efficent brains, it is possible that they may have developed human levels of intelligence.
I also note that some extinct flying creatures have had body masses equal to or greater than an average human. Thus it is theoretically possible for a flying being to have a brain as large as human brain.
Argentavis magnificens was among the largest flying birds ever to exist
The mass is estimated to be about 72 to 74 kilograms or 154 to 159 pounds.
https://en.wikipedia.org/wiki/Argentavis
The largest extinct flying reptiles were even larger.
Quetzalcoatlus /kɛtsəlkoʊˈætləs/ is a genus of pterosaur known from the Late Cretaceous period of North America (Maastrichtian stage); its members were among the largest known flying animals of all time.
Body mass estimates for giant azhdarchids are extremely problematic because no existing species share a similar size or body plan, and in consequence, published results vary widely.3 Generalized weight, based on some studies that have historically found extremely low weight estimates for Quetzalcoatlus, was as low as 70 kg (150 lb) for a 10 m (32 ft 10 in) individual. A majority of estimates published since the 2000s have been substantially higher, around 200–250 kg (440–550 lb).[12][13]
https://en.wikipedia.org/wiki/Quetzalcoatlus#Size
So it is theoretically possible for a flying animal to have a brain large enough for intelligence, even if a brain the size of a human brain is necessary for intelligence.
Some cephalopods, like octopuses, display high intelligence, and thus it may be possible for some cephalopods to be intelligent beings.
I once read that hundreds of thousands or even over a million giant squid might be eaten every day by predators. So I certainly hope that giant squid are not intelligent.
You might have heard the song "Octopus's Garden". There is a theory, which is not widely accepted, that a fossel of a prehistoric cephalopod's garden under the sea has been found.
In 2011 it was suggested that the vertibrae of ichthyosaurs found in a strange double line might have been arranged by some really gigantic cephalopod which had killed them. Which suggests a highy inteligent giant cephalopod playing with the bones of its food and possibly arranging them to look like the double row of suckers on a tenticle.
https://www.nature.com/articles/news.2011.586
So possibly there was a species of intelligent giant cephalopods in Earth's oceans 228 million years ago.
So it is possible that there have been many species of inteligent beings on Earth, on and off over hundreds of millions of years, with several different major body plans and many more minor variations on each body plan.
So it seems impossible to predict the appearance of intelligent beings on Earth from the environmental condiitons on Earth.
And the same difficulty in predicting the appearance of intelligent life may go for other planets with life.
