I faced more or less the same issue when my daughter was born. We moved 2 weeks before her arrival and my son was 18 months. We decided to buy another crib.
My kids are now 3 (almost 3 1/2) and 1 1/2 ( almost 2) and my son stayed in his crib until shortly before his 3rd birthday. He does not get out and wonder at night. He loved his crib, and it was easier to transition out when he could fully understand that it was because he was a big boy.
Also, in terms of night training for potty training with a boy, boys take a lot longer, my son still can not go the night without a diaper but otherwise is fully potty trained.
I recommend getting another crib, it worked for me and keeping them in a crib is better because then you don't have to worry about night wandering when you have a newborn as well. In addition, a new room is a big enough change, so keeping his crib will add some reassurance for him.