It'd be easy enough to do. If Chris is still keeping up his childish charade by then, all that he has to do is screech, 'hey, the Brony Analysts! Mama really loves them, and so do I!' at the start, and he's good to go. Chris has even said that he thinks Sonichu sounds almost exactly like himself, so he won't even need to attempt a different voice. After that, he can just gurn uncomprehendingly, screech laughter at silly noises, and suck anal cyst arse as per last time.
Edit to add: And, of course, the first TF2 reaction video was released in mid-April. Chris claims to have body-swapped with Sonichu at the end of March. So the first video was, presumably, hosted by Sonichu, not Chris. (Even though Chris announced it, and lightning bolt-blue heart-lightning bolt signed the announcement, as himself.)