Well that's useful.
I've done all the other stuff, but I don't see how you're getting BTC to run properly with a blank rpc user/pass. If the bitcoin.conf has "rpcuser=" and "rpcpassword=", it's smart enough to know nothing is there and instead spawn and use a cookie file for the relevant info.
Unless I'm missing something, if we want to allow the user to operate COMB without using a config, then we need to set default info (i.e. "user" and "pass") and tell them to insert those into the bitcoin.conf file.