Congrats!!! I'm sooo excited for you!!!
Do you have a step-in harness for him? Its very important that you don't attach his leash to his collar as he could get damage to his little throat, these are very delicate babies even the bigger ones are still small dogs
I do use collars with an ID tag incase they should manage to get loose but never attach a leash to them, they all have step-in harnesses even my giant OESD!
As for the name, I have changed an adult dogs name in the past. I did keep it similar from Sea-bass (as in fish WTH
) to Sheamas, we had no problems. If you really don't like his name then change it something better. Afterall your baby is getting a new start in life!!!