"1 or 2 friends is enough" or "1 or 2 friends are enough"

Solution 1:

To me, the singular/plural issue depends on what "enough" refers to; whether it is used in a quantitative or qualitative sense, or at least a countable or non-countable sense.

If "enough" means a sufficient quantity of people in a countable sense, it would be "are": "1 or 2 friends are enough to move the couch."

If "enough" means sufficiency for a qualitative criterion, it would be "is": "1 or 2 friends is enough to make me happy."

That said, I can think of an example that seems ambiguous:

"1 or 2 people are enough to feed a village of cannibals." This would be in the countable sense of a recipe: 1 bucket of potatoes, 3 bunches of carrots, and 1 or 2 people.

"1 or 2 people is enough to feed a village of cannibals." This would be in the non-count sense of the village having a sufficient amount of (non-countable) food (and it's really referring to people meat that has been divided up or consumed, rather than countable people at that point).

I changed "friends" to "people" because even cannibals don't eat their friends (well I'm just guessing on that point).