I'm not sure what you're trying to do here, but beyond the start dates that are in the game, some of which have their own issues, you likely won't be able to start at a later date, especially one after 1948, just by changing the defines.lua files. Well, you can, but as you've experienced, the game was made to model ww2, and thus you inevitably get some weird stuff if you try to make it model a post-war world by just changing the start date. If you want to play a post-war game, I'm sure there is a mod somewhere to accommodate you.
Alternatively you could start a game as Panama, or another micro power, in 1944, and play out the war (or change the date, though I suspect the result will be different). You'll probably get a slightly more realistic result. A German win is very unlikely in the 1944 scenario, while it is very possible in the 1936 one. Then you can thinker with it by tagging to various nations to create puppets, and by editing the map province by province. For India and Egypt you can 'liberate' them as the UK, and there is a way to turn those puppets into independent states. (Though I don't remember how exactly, it can be found on this forum).
If you link your game key to your paradox account, you can also access the modding sub-forum.