UKC

Appreciate this is a novice question, but this is the earliest I have visited the Cairngorms and I have been seeing snow forecast on the peaks. Would you advise packing a B2 boot (Manta Pro) or is that too much horsepower for a couple of days hillwalking and wild camping over the next week?

I think you are definitely making the right choice here.  the MWIS is talking about sub-zero temperatures and snowfall so yes, you need something with some winter capability.  I was once in the Cairngorms for the early May bank holiday and there was plenty of unavoidable snow around, albeit not frozen at that time but if I was spending the night up there...

No harm taking your winter and summer boots with you to the car park and assess conditions from the car then make a decision on what you're going to wear. There's barely any snow outside of gullies right now although think some light snow is forcasted over the next week