First off, up here on some of our reservoirs, a 25 hp 4 stroke is all that is allowed. Using an 18' open (tiller steer) Lund with 3 anglers and all the gear, we were easily able to get up to 20 mph (GPS calculated) and on plane easily. Hull design can be a factor however. I would be concerned with the weight if you plan on 3 adults, a teenagage and all the gear, but the problem I see is space, more than power. That's asking an awful lot out of a 16' boat of any kind in my opinion. Good luck on your choice.
BTW, have you compared boat mfgs. specs as far as width goes? 4" one way or the other can make a significant difference as far as fish-ability goes with that many people. When I had my Crestliner (years ago!), it was the widest hull on the market. You'd do well to look at boat specs and comparisons. It's a daunting decision - I know!
"A voyage in search of knowledge need never abandon the spirit of adventure."