This is such a delightfully alien --- but creepy and unpleasant --- idea for a PC. It's probably going to be difficult for a DM to work with, especially with the infinite, but short-lifespan, better-than-zombies. So I agree that the asterisk is warranted. There's also a bit of ambiguity around the mind-affecting and intelligence-consuming special attacks, especially with regards to how someone can be rescued from them. For example, the conditions required for breaking the mind control and ending the brain-eating are different, but there aren't any provisions addressing what happens when one is broken without the other. You could hypothetically break the mind control through some means or another, leaving an uncontrolled victim inside the plant. Presumably, some kind of grapple rules might come into play at this point, but that's not addressed. Or, some text implies that you can extract a victim from the plant, but by RAW the brain-eating continues until either the victim or the creeper is dead. It shouldn't be too tough to make some decisions, but this is something the player and DM should consider beforehand.

And it will also be tough for a player to use a musk creeper PC in a lot of situations, so that will definitely keep it from having too high an LA. In my pre-vote, I gave it +1*, mainly because of (Ex) mind-control (which bypasses many countermeasures, like the resurgence spell) and six melee attacks with reach. But, now I realize that there isn't a Trip or Improved Grab on those (which I think I had assumed before), and I'm also thinking that the mindlessness and slow movement speed are much bigger hindrances than I previously appreciated. Personally, I'm a fan of allowing free "awaken" effects for monster PCs, but I'm just starting to appreciate that that's not necessarily a given for all DMs. So, I think my vote will be LA +0* for the yellow musk creeper.