There were about 4,500 Spitfire LF.Mk IX/Mk XVIs made. They are the same plane. LF.Mk IXs entered combat in 1943. LF.Mk IXes in mid 1944. Mk XVIs in mid 1944 as well, but as noted, they are the same thing, just with an American built engine that needed different tools to work on, hence the new mark number. They came off the assembly line intermingled with the mark not even known until the Rolls Royce Merlin 66 or Packard Merlin 266 was mounted.
There was, interestingly, a slight difference. The Packard Merlin 266 had a critical altitude 1000ft higher than the Rolls Royce Merlin 66. In AH the Mk XVI's critical altitude matches that of the Merlin 66, not the Merlin 266, and that means the Mk XVI in AH is actually an LF.Mk IXe, which first saw combat in the first half of 1944.
On topic:
What would an Ohka at the port do? It can't launch itself. It needs to be dropped by a mothership, a modified G4M2 (we have the G4M1 in AH, not the right kind of Betty) about 20, IIRC, miles from its target.