The tape pause mute thing only happens when you modify a tape head unit directly. The aux tape unit does not do this.
As far as the cd/aux vs. cd/play button, I think they're the same thing. I think the people at PAC really don't pay that much attention to the button's label. I do know that there is a unit that does work for sale over on CGP at the store.
The aux tape unit really isn't that much trouble once you find a place to put the tape unit. I found that mine fits nicely in the glovebox with the equalizer/pre-amp...
The FM modulators are just a tick above crap when it comes to sound quality, and the cd to cassette adapters just plain suck... (IMO)