DW,
If you are saying that the catholic church retrospectively slapped the title of bishop onto very early overseers in an attempt to tie them to the catholic church, maybe you're right. I don't know.
The earliest mention of the word catholic that I could find was 110 ad, so that's actually quite early and there would have been people alive that may have been contemporaries of some of the disciples. The muratorian fragment also mentions the word catholic.
What would become the catholic church was responsible for compiling letters of the apostles and letters of correspondence between early congregations, preserving and copying them. The church claims an unbroken line of successors of the apostles. So I guess the sticking point for you is, at what stage did Christians become catholics?
The article I linked was another example of the disingenuous writing style of the wt. They tell part of the story so that reader is never presented with the full picture.