Firstly, when the host is affected, their body will grow bigger than it would have originally been, but not much bigger, only about being 1/2 times bigger.
Depends on the host, but if the animal species was one with indeterminate growth then obviously it is set up to get bigger, only there's a reasonable chance it would get bigger anyway. Maybe the virus accelerates the process?
For species with determinate growth (such as humans) physical maturity is marked but a bunch of physiological changes that effectively end any further growth opportunities. In humans for example, bone growth plates simply ossify, and no further growth is possible in most bones.
One major thing that’ll change is that the host will become drastically intelligent, being on par with human intelligence.
Human brains are the end product of a very substantial amount of evolution, and modern human intelligence is at least in part due to thousands of years of cultural evolution. Your brain is made up of a vast network of interconnections that grew during your physical development in response to outside influences over many years.
You can't just handwave that sort of thing in overnight; if nothing else, viruses just aren't going to be able to encode enough information in their own genome to impart that level of complexity.
This will allow the host to have the ability’s to do things such a telepathy and telekinesis, it’ll also allow them to talk to other animals.
Lets assume that you have human level intelligence. Do you have telepathy and telekinesis? Again, I'm gonna assume no. One does not follow the other.
Wait, wait. You've flagged this
reality-check and you're asking about telekinesis and telepathy? If this were the 60s or 70s, maybe, but science has marched on in the last eighty years. Be serious now.
Animal mimicry is possible, of course, but it either has to be learned, or a lot of sophisticated (and very host and target species specific) information needs to be encoded in the virus.
Lastly, it’ll allow the host to develop a biological EMP ability,
I feel like you're just yanking my chain, now.
but will also allow for them to manipulate a creatures mind and also allow for them to mimic certain calls and rarely abilities