Any low cost 2G4 set that does not have "Park Flyer" on the label will do the job. Park flyers are intended to be short (i.e. almost within reach/indoors) so not a lot of use where lost control out of reach on water is acceptable.
Servos are nowadays universal in that they plug into any receiver, just a question of plugging them in the right way round and actually on the receiver pins. Ordinary "standard" servo for steering, a "high torque" but same size version for the sails. Arm type sail controls do need very firm fixing, every action has its equal and opposite reaction, and while the arm is pulling at the sails, the body is doing its best to twist out of its mount.
Not a huge boat, so just use a 4 or 5 cell AA rechargeable receiver pack. Enough power and capacity for a satisfying sail, light enough to not weigh the boat down excessively. A bit of wiring loom with a switch to connect between battery and receiver will help.