I’ve used the hot iron plastic welding on quite a few different plastics over the years. One thing I can say is almost all plastic is different which means they all melt at different temps and react a different way. There’s a fine line between melting enough to fuse it back together and burning it. Fusing two plastics together to hold and doing it to prevent leaking is a whole different animal. Some plastics just can’t be melted using a soldering iron to where it won’t leak. Might be worth a shot as long as you leave enough there to where I plastic welder can still fix it if it doesn’t work out.
I would just cut out the old, burr the opening a little to clean it up, and put a whole new bulkhead fitting in.
