The main decision is between a petrol outboard, and a diesel sterndrive. Other options are generally of little interest for cruising RIBs.
The major benefits of diesel are fuel price and availability. Outboards are cheaper to buy, but are much more expensive to run and often involve lugging jerry cans around.#
My choice is a diesel sterndrive anytime -- for your size range the two most popular options are the Yamaha (240 hp) or Yanmar (300 hp).
You will want a deep V hull for offshore cruising: Ribtec, Ribcraft, Scorpion, Delta would all be worth a look.
PS Do you still have any crew? Do any come out a second time?
PPS Your caps lock key seems to be stuck