You're definitely correct to note that because this is a retro-fit, the sharkbite/push-fit stuff would probably be easier.

The only thing is, they're much more spendy than the clamp/crimp fittings (see this vs. this and this vs. this, for example.) The clamps/crimp rings cost a little bit, but still, it looks like I'll spend at least 4x as much for the push-fit stuff. Maybe the ease of installation is worth it, though...

I have forced air heating, so no need for any of the heating stuff you mentioned.

EDIT: Re: Sharkbites... One downside I can think of is that the perception that they're not as tried-and-true as other connection methods could lead an inspector to say they're unsafe or not up to code. There's a perception that they're fine for temporary connections, but that in-wall connections should be done with crimp rings/clamps. Even if it's not true, the perception could cause me to have problems with the inspector...

EDIT #2: Also, how about the fittings that have to attach to copper? From what I've read, the sharkbite uses a steel ring to grab on to the copper. Isn't there a strong possibility that there's a reaction between the dissimilar metals?