2) is
not coastal, but close to the coast.
3) is
not an important military centre
4) is
not an important trade centre (all my coastel ones are important trade centres, but sometimes inland cities are rich as well)
Well.. the thing is..
Once your up and running money's not really gonna be an issue and depending which faction your playing, city units may not be battle worthy at all. Take HRE for example por sods, a castle faction if I ever saw one.
So...To my mind it's all about expedience. Once you have a Cathedral & a theology guild up and running, each new priests are now Bishops and the papacy belongs to you.