Well that was braver than I. That would have been a job for Dave. Seems like no room to work is the biggest issue.
Removing the front mount and raising the engine a few inches makes it a much easier job.
And I wouldnāt be surprised if the water pump failed within the month. It often happens that way.
Do yourself a favorā¦ @Bugmenot provided you with the diagram to referenceā¦ Go to a dealership and buy that #3 part (Stud) and it will tell you everything you need to know about what threads are whatā¦ Before you go assuming things while trying to extract the remainder of the stud. You need to know precisely what is what in that process.
After thatā¦ you have plenty of material to work with, shouldnāt be very difficult at all extracting that piece. Some heat will surely helpā¦ a welder helps even more (to make a tool or simply weld a socket onto the end and extract)