Here’s the deal: he’s in the room, so you options are either to talk about him or to pretend he’s not there.
You can put it off, you can discuss other things, you can hide for a while, but he ain’t going anywhere (heck, he doesn’t even fit through the door).
Imagine how you’ll surprise people when you – you who appear to have most to lose if you bring him up; you, whose plan seems to hinge on him not being there at all – call him out, describe just what he looks like, acknowledge that he could scuttle everything.
Better for you to name him and explain why it makes sense to barrel ahead regardless. It’s when someone else calls him out that you’ll be pushed onto your back foot and risk losing momentum.