The Water placement mod is just that the ability to place infantry units in a water location and contains no models. It was designed for placing troops for a beach landing but works well for oil rigs too.
The medics can be found here in the mission editor when the HARRIER mod has been activated:
Upuaut made some excellent medical tent and ambulance mods quite a while ago so I recommend doing a search for those. I think the ambulance was part of his Wolf vehicle mod. To my knowledge there are no medical staff mods...Doctors etc. I made this MASH Unit for PG Map, using them.