Overall, advice would be don't create cost or complication that won't provide sufficient benefit.
You planning on messing with handicaps/net scores or no? planning on addressing that through flights? In my experience that's hard to do competitively. Would recommend just asking for handicaps, and using the 20A/15B/10C/5D method for calculating a group handicap.
Is this mainly a fundraiser? Would limit expenses then accordingly - e.g. prizes, some courses (may be regional) will provide some prizes if you ask (e.g. the free rounds, putter, etc.), trophies may be enough.
Pricing is hard to judge - regional, and depends highly on the quality of the course. If this is a top notch course and a regular tournament, looks ok. If this is a first time event and a mediocre or worse course and event that doesn't have a track record with past sponsors, those mid levels might be a little high.
Hole in one prizes are generally insured and a pain in the ass to set up accordingly for something that generally doesn't get people excited.
Mulligans are a good extra fundraiser, as is (used to be the "Tiger" drive, I guess now it's the "Bryson" drive?) where you set them up like 350 yards down the fairway on a longer par 5.
Some side events are going to be more pain in the ass and distraction than quick money maker. Putting contest is in that bucket. Raffles can work, but depend on the laws in your area.