Just getting some fox float 32s to go on my Zesty 314 (mainly cos I wanted bolt through). This will raise the travel from 140mm to 150mm

Can't imagine than an extra 10mm travel is going to upset anything too much. In fact I could do with raising the BB a smidge.

I guess I can also increase the sag a bit if necessary.

Or am I going to die horribly?

A fox 150mm is the same length as a rockshox recon 140 i think, and they put that on the cheaper model, so yes it'd be fine