Doesn't look as if he was house trained very well, does it?
So does it make sense to try and stay "consistent"?
Build a bond with the dog. Give him house freedom only when he earns it.
Research the correct use of an e collar or get rid of it and train the dog. Whoever gave him up probably used that thing with no clue, and when they got bad results they dumped the dog.
Norden von Narnia (Hans) DOB 1-15-2012