I wouldn't be offended at all - those sounds like neat ideas.
Feel free to use any of the code you want.
When I wrote the code I was still exploring the various data structures Java has, so the ship and fighter tests are done using set operations that don't count the number of ships, just the types. So in order to do specific numbers you'll have to rewrite the guts of those functions (and probably make it just one function for both, its like 99% code duplication and I'm kinda embarrassed I left it like that).
Also, be aware that some IO stuff is locked as part of the game security - I think external json files would be ok but I'm not sure (I'm sure someone knows so we can ask on the misc modding questions thread).