I'll try to predict, how humans will live with higher/lower gravity.
Soviet Union cosmonaut Valeriy Polyakov had spend 437 days and 18 hours aboard Soviet Union Space station Mir with zero gravity. He totally spend more than 600 days in space with zero gravity. He is still alive. So, lower gravity seems to be not so fatal. Its worth notice, that 'Mir' station had a lot of physical training apparatus to keep cosmonauts healthy.
For slightly higher gravity - there should be much more pressure on blood system - so, human will have lesser endurance, and higher risks of heard attacks and thrombs - because heart will have to pump little heavier blood, and spend more energy on it. But, if you spend more time laying on back, your heart will rest.
For slighter lower gravity - there should be issues with digestive and Lymphatic systems - they evolved to work in 1G environment.
But, on same time, humans are very adaptable. Compare Chuchki people, who lives in on shores of North Polar Sea, and Bedouins from Sahara, they are same humans, but they live in very different conditions.
I think during few generations humans can adapt to either higher or lower gravity.
So, there should be more muscular and short dwarf like humans who prefer higher gravity, and more slim and slender humans who prefer lower gravity, and they will be able to have nearly normal humans lifespan, if they live in environment, they adapted too.
But, on same time, they can probably spend few months per year in regions with different gravity without any meaningful degrade in body functions.
For non humans. It depends, which creature it is.
If its aquatic creature like dolphin or fish, they will probably not notice change of gravity.
If its avian creature able to fly - probably it will be unable to fly properly at higher gravity.
If its non biped creature 4 or even 6 legs - it will probably survive higher gravity easier, that biped