Saxman there is quite a backlog of terrains being built for Scenarios and FSO right now. Plus, Dux can speak to this specifically, but building a terrain is rather lengthy .. getting the terrain in place is one thing. Skinning it with the tile you want, build the strat system, placing the bases and other objects, etc., etc. takes time. Then it has to be tested, reviewed, etc. to catch bugs. As said it is a lengthy process.
So since this is just a design exercise have at it. But Fencre51 does bring up a good point.
Any FSO starts first with what terrains are available or will be available and tested for stability by X time period. Quite a few of my FSO designs have been shelved waiting on terrains (right now waiting on Tunisia and Luzon came out just a hair to late before so ran Guadalcanal).
After that is to come up with an idea. You are doing a good job with that.
After that is play balance. Both sides have to have a good shot of winning. Your planeset here needs work. A6M5 / A6M2 is at definite disadvantage versus the F4U-1 and P38G even in limited numbers. In Aleutians the frame that had limited P38Gs .. well they romped on the A6M2. Against the P39D and F4F-4 they definitely can hold their own (although have to be flown well .. less room for pilot margin).
So I would modify it for the naval portion that only carrier planes available (sans the F4U-1). Then after or I should say if the Japanese get a land base you could activate the F4U-1, P38G, Ki61 and JU88s.