as long as you can produce correct nbits for the next block (15 lines of c++), validate the previous header hash (using openssl lib, 5 lines of c++), you can test to see whether the blockheader you received is indeed accurate.
I didn't mean this. Sure, you can write a program that checks the validity of the block header, but if you haven't verified the entire chain until that point, you can't know for sure what's the previous block hash, for example.
not including transactions (since you wouldnt know or be listening for txes) would actually improve your chances of nailing a block.
Yes, but it's little matter when it comes to earning millions of sats in fees.