While you are looking for a trainer here's some things to start working on his behaviour.
One big one, if he's being held and goes to nip someone he immediately gets put on the floor. Alot of little dogs will start to do this and being continued to be held will reinstate the behaviour.
For outside, give the dog a job. Teach the dog to push a ball around or run around with a chew toy. If your smart dog is bored they will find a job for themselves, hence the barking.
The dog should not be going out on it's own ( I know you know this), he needs to be taught to respect open doors and not go through them until told that he is allowed.
If you want tips on how to teach this you can email me
TotorosBowl@gmail.com
I would suggest TNT Training in Abbottsford. They have a toy dog training classes and will be able to help address the issues you are having.