That'll be tough to do. Not impossible, but tough. A Jet with that kind of reliability is either a blue-printed Berkeley or Jacuzzi, or a Hamilton out of the box. I have not met a Panther or other stern mounted jet that was very reliable. If salt water is in the equation, it's down to Hamilton ...
You already have a big boat, so what is this smaller one for?
The best of these smaller ones are built for river fishing with upstream rapids as an issue. Shallow draft, good pumps, welded hulls, V-8 power
A few folks try Jet outboards. Usually not very satisfied... Fuel burn is very high and they get tore up pretty easily...
Kawasaki, Yamaha and others made neat little runabouts with PWC power - usually dual engines.
If you could find a low time unit from a Grand-Pa (estate) who had a cabin at a lake and bought it for the small kids to go out on with him, that would be a cool deal. Otherwise you need to be real careful about wear and tear... I think that's what most of us are saying