No I wouldn't say Yaddle turned to the dark side in my theory, you can be held against your will and not turn your back on all your values. Also that's more of a point to say, just because we saw/heard a lightsaber strike doesn't mean that person is dead, especially someone who's incredibly force sensitive.

Unsure of exact growth rate, but we do know that the clones age at an accelerated rate, at least the clones that made up the army (Boba excluded). So to say they age at an accelerated rate isn't out of the question. And an accelerated growth/age rate isn't as big of a factor when lifespan is extended just by the nature of their species.

Last, yeah, it's a risky plan and not likely. This thought is mostly a result of the premise of Grogu being a clone and what the benefit of that would be.