1 - no, anopes DB's are binary and editing is not supported. if you wanna run devel, there s slightly better chance you may succeed, but we still won't support it..
2 - sure, just unload cs_register and the register command will be gone. or restrict chanserv to opers.
3 - then how would that user identify..

Anope - for now - requires the user to be using the nick he wants to ID to..
4 - depends on your ircd, on most that ll be +R.
5 - anope doesn't log what happens on channels. it can optionally log joins and parts, but it won't log the content of a channels traffic.
and through modules anopes behaviour can be modified greatly.. if standard anope can't do something, chances are that with a module it s possible.. whether one already exists that does what you want is another matter.. just check the modules site..