Ive done a few searches but its not got me anywhere, I am thinking of going 650b on a new frame and wondering if the fox lowers could be swapped on my 26″ Floats? or were they completely redesigned!?

Yes it can be done I did the same thing with a set of 26″ 34’s and just bought 27.5″ lowers they will bolt straight on.

Good to hear, as this is probably my next move ( once I have worn through my mountain of 26inch rubber…) but have a straight 1 1/8 steerer. Does having talas make a difference to lowers?

Buy a set of 2nd hand 650b forks instead of just the lowers from mojo. Lowers will skin you £208 not including decals and postage. Buy a set of forks, swap the lowers and sell them on. I paid just over £200 i think for some forks and then sold them with 650b lowers for £170-180.