I'm going to start running the Malevolence AP tomorrow, any advice specific to the campaign? Particularly interested in advice about how to handle the research section
I haven't read or run it myself, but just a heads up that Malevolence is an Adventure, not an Adventure Path (AP).
Pathfinder's APs run over several volumes (either 3 or 6) and extend over a number of levels (typically 10 for the 3-volume APs and 20 for the 6-volume ones, at least for the 2e ones), while Adventures are much shorter.
Ran the first session last weekend, I think it went pretty well. Forgot the saving throw for Malevolence for the minor haunts but otherwise mechanically went smooth. The ambiance was good, they seemed a little unnerved by the atmosphere, we didn't get too far into the adventure after character back stories but next session we should make a lot more progress.