ill tell you all i know, which isnt a lot but it may help a little.
ok so.. first. he is not too old. i hear that with the barking what you have to do is IGNORE it.. that doing anything in response is giving them the attention they want, negative
or postive. what i do with pebbles is praise her when she is quiet. i read this in my training book. i say "GOOD QUIET" and pet her etc. if she starts to bark again i immediately ignore her again. it seems to be working with keeping her quiet when i want to. however dogs do bark to communicate so its hard to cut it out completely.
you have to teach him to associate coming to you with good things.. dont ask him to come if his "reward" will be "you being mad" .. he wont come. when he comes give him praise and treats only
my puppy still bites too but she is getting better.. when she bites too hard i give a little welp sound like OW that was PAINFUL and she seems to get the point that it was inappropriate. and then she bites a little less hard the following time
as for potty training... you cant half ass it
you gotta go full on potty training/serious business, and do the whole watching him at all times/correcting him/taking him to the paper, or the crate training him thing. there are many threads on how to potty train, check some of them out