It's a WIP roll. It says "By passing a WIP Roll, the user enters the Impersonation-2 state." All other Supportware doesn't need a roll so it's not a silly question.
And am I right in thinking that you can only have 1 gadget up at a time? So in a turn I can put 'assisted fire' on pi-well go and shoot stuff then with my last order take that off and put on 'enhanced reaction'??
Yes. Only 1 Supportware per Hacker and a single REM can only benefit from 1 Supportware at a time (although they can be affected by several at once because of how the Gadget EVO Supportware programs work, in which case you choose which you want to apply to a particular order). From a Gameplay POV, there's a fair chance you're better leaving Assisted Fire on and putting Pi-well on Suppression though.
Seconding this. Losing cover bonus and getting shock ammo is pretty nice in the reactive as well. Even in a situation where the +1 B would be more advantageous, it's probably not so much that the order couldn't be better spent on something else (like suppressive fire).