It can change forms on levels that are a multiple of 5. It will not affect making a rati. As long as you have the right stats and it's on the right character at level 100, it will become a rati.
I would suggest FOmarl for obvious reasons. And a 0/136/72/2 tellusis, love rappy, ultima, soniti, sato or nidra would be op. It also can make a robochao with those stats.