I recently moved to Belgium from Germany. Is there any way I can transfer my PS Network account info and games to the European PS Store before I pay for the PS+ package? Also, would it change the PS Store language so it isn't in German anymore?
No. Profiles can't be moved across regions. If you're not going to have German billing information anymore (address / payment method), then you'll need to either buy German PSN points, etc... from an online retailer to keep things consistent. Or setup a second account for the region you now live in and use that for purchases going forward.
Frankly, if you have already bought games and have trophies, etc... under your German account, just keep using that account. The devices don't care where you are and you can play local content even on a device homed to an different region. It only gets tricky if you want to buy DLC.