I have a few suggestions for what the Alien creatures might look like:
Feline
Dragon Ears
Thick Tail
Neon Coloured Tiger Stripe (Body)
Neon Coloured Eye Stripe (Head)
Neon Coloured Snow Leapord (Tail)
Crimson, Azure, or Forest(Eyes)
Now, going back to the mutated dogs, I have a few suggestions for them, for they're powers and stuff, considering that there would probaly be a variety of powers because the humans don't want all of them doing the same thing.
Lazer eyes- Mainly for an attack that coudly possibly burn the aliens.
Super Strength- For inflicting great damage on enemy, though dogs with this power can't withstand much.
Armored Body.-Basically, the dog can withstand most attacks or a variety of attacks for awhile, while inflicting little damage on the enemy
Invisability- It would come in handy when you need to use Ninja skills.
Teleportation.- When you need to teleport to the enemy! BDD It'll confuse em' too owo.
Super Speed- Useful against an enemy that's faster than the other dogs.
Telepathy- Read the enemies mind, find out where they're attacking next BDDD
Super Sense- So you can see, hear, touch, smell, and taste the aliens before anyone else. (Taste...? O.O)
I hope these come of use` XP