It's a very bad idea indeed. It will ruin PVE queues completely. You might have to wait for ages, not knowing whether there will be a match at all. Why queue up in the first place then?
This even happens by just dragging it into one of the slots in the upgrading tray, and without using a kit. If that is meant to be like that I'm angry - or is it a mistake?, then please fix it.
For PvE: Having tested a lot of pets in sb234, I can say that elite swarmers are the best dps-wise. If you have no access or if they are too expensive, go for elite scorps. For PvP: No idea. Greetings