I think it'd be entirely possible, the only real problem I can think of is what Morf pointed out, you go into a trance when being acquired... But, if you can acquire from blood, then problem solved, or, even from maybe hair, spit, et cetera (as someone else pointed out), that way, you could morph your younger self when you were old and grey, and get an extra 30-40 years, or more if it was a young enough morph, and, if they can figure out how to give the morphing ability to nothlits, then, yeah, there's immortal-ness possibility.
Plus, you'd get to go through the rest of your (newly elongated) life with thought-speak!
And, personally, I believe the reason you can't acquire dead things is a safety feature the Andalites installed. I mean, honestly, if you developed the morphing power, wouldn't you install the same safe-guard? You wouldn't want people killing someone, and then morphing then... A whole new level of ID theft! Lol. Although, on the same hand, you could just acquire them and then kill them... Which would actually be more helpful... Considering it puts them in a trance... Alright, I'm getting WAY off topic. XD Stupid not sleeping for days....