Do the Bugbear's Long-Limbed trait and the Way of the Astral Self's astral arms stack for reach?

Question

The Bugbear has a trait called Long-Limbed that states:

When you make a melee attack on your turn, your reach for it is 5 feet greater than normal.

The Way of the Astral Self monk has a feature called Arms of the Astral Self that gives the monk many benefits, but the ones I want to focus on are:

You can use the spectral arms to make unarmed strikes. When you make an unarmed strike with the arms on your turn, your reach for it is 5 feet greater than normal.

Do the reach increases from Long-Limbed and Arms of the Astral Self stack?

Answer 1

Yes, they stack: your reach is 15 feet.†

Arms of the Astral Self and Long-Limbed are game features with different names, so they can stack, even though they provide similar effects. Per DMG errata, emphasis mine:

Different game features can affect a target at the same time. But when two or more game features have the same name, only the effects of one of them—the most potent one—apply while the durations of the effects overlap. For example, if a target is ignited by a fire elemental’s Fire Form trait, the ongoing fire damage doesn’t increase if the burning target is subjected to that trait again. Game features include spells, class features, feats, racial traits, monster abilities, and magic items.

Additionally, per an unofficial tweet by rules designer Jeremy Crawford:

The rule on combining game effects applies only to effects with exactly the same name.

Relevant Q&As:

• What are the practical Opportunity Attack values for a bugbear, holding a reach weapon, with the Polearm Master feat?
• At what distance can a bugbear, holding a reach weapon, with the Polearm Master feat, get their Opportunity Attack?

† Sidebar: when each feature matters

Long-Limbed applies to melee attacks on your turn, but Arms of the Astral Self applies to unarmed strikes, with the arms, on your turn. They stack only if making unarmed strikes (which are melee attacks) on your turn. Off-turn, neither applies; with any weapon other than your arms (including your legs, head, or tongue), only Long-Limbed applies.

Answer 2

Each feature only makes your reach 5 greater than normal, so they do not stack.

Each feature contains the text:

your reach for it is 5 feet greater than normal.

"Normal" here refers to your unmodified reach. Thus, each feature requires that you take your unmodified reach and add 5 feet to it, resulting only in a reach of 10 feet, even when used at the same time.

Suppose we use Arms of the Astral Self, now our reach is 5 feet greater than normal, which is 10 feet. Then, we make a melee attack, triggering the bugbear's Long Limbed feature, that again says our reach is five feet greater than normal. But this was already true because of Arms of the Astral Self. The 10 foot reach we have from Arms of the Astral Self is not our normal reach, so Long Limbed does not add to it.