First, I have to say no. At present, characters will all begin with a single Echo. It might take some creative thinking to get them involved in a case like you've outlined, but that'd just have to be part of playing a character like that. The only exception is characters starting as animals have the option to have speech picked up alongside their sentience. So long as speech was a part of their preincarnation, of course. Later seasons will allow for applications of characters with several Echoes, but that's way in the future and when circumstances will have changed considerably.

Second, it's possible, and the result would be exactly the same as if they infested any other small creature.