David, hello
life rafts on work boats, I include tugs, harbour boats and fishing boats, would normally have it stowed on the cabin roof with a hydrostatic release valve fitted. Because these are working boats they are stowed out of the way but are instantly available as the, and I'm sorry to say it, usual accident with these vessels is capsize without a lot of warning. The tow rope slips around the side, an anchor slips its position or the towed gear gets stuck on an under water obstruction, 20 seconds later the boat is over, hence the stowage on the roof so that it can release free of the deck for the unfortunate crew to find.
Stuffed against the bulwarks it could get trapped, or damaged during work etc. So I'd say on the wheelhouse (if it has one).
As to lights, yes, all boats at sea require lights, even a row boat should have at least a torch to indicate it's presence to other shipping. Also, workboats might well carry day marks and associated lights if working at night. As Ashley says, have a look at some images of workboats on good ol' Goog', there's loads of bits and bobs you can add.
For navigation lights have a look at the IRPCS, regs for prevention of collision at sea, that will soon give you the idea about lights and what type is required by what vessel..
Its a subject close to heart. Aye, Kimmo