Thanks to you both for the thoughts and the feedback.
In addition to reading your posts and poking around more online, I've had several conversations with manufacturers about how their products integrate with Crestron. So far, I've chatted with Meridian, Digital Watchdog, Zodiac (Aqualink maker) and will likely do a few more. LIke I said, I'm technical and like to know how these things will work before I jump in.

Here are a few thoughts I have as of now:

1 - I always planned to have hard button handheld remotes in all video zones. My wife would never go for a touchpanel/iPad only solution. Tried that years ago with the old Phillips Pronto and she hated it. This is one of those areas where muscle memory is way more useful than the touch panel's flexibility. I will be checking out the MLX, MTX and TPMC to see which works best for which zones.

2 - My thought on iPads is in lieu of the larger, usually wall-mounted, proprietary panels. The home currently makes use of them in the system for this purpose. I have gotten some feedback though that is making me think about how a few panels could be useful. For one, they would be wired and therefore not prone to wireless issues. I will be investigating to be sure, but the home has been outfitted with a built-in WIFI network to allow for those iPads to have reliable signals. Even so, I can still see how wired panels would be useful fallbacks. In addition, a wall mounted solution never runs out of battery charge, doesn't get lost, dropped, etc. Depending on cost, I could see doing one per level.

3 - All lighting controls will have hard button switches in the respective rooms. This is another nod to my wife. While extensive scene controls will be accessible from more complex interfaces, she's just going to want simple and reliable hard buttons. It's that legacy nod to what we have now to simple, dumb switches, but I can't expect her to radically change behavior on something like this. That being said, I'm also interested in room sensors that could allow for lights coming on automatically in some rooms when people come in and turning off when they go.

4 - I'm going to have to think about quick access audio control. Sofa King's thought is a good one as I can totally see the need to quickly mute/unmute audio, like when a phone call comes in, etc. There are a bunch of ways that could get implemented, so I'll have to run through that with the installer. The keypads may be a cost effective route, especially since hard buttoned lighting control will be a must for my wife. I definitely know that I don't want the Sonos handling volume control or zone grouping - that should be handled by Crestron.

5 - One thing that appears more clear to me now is how I could actually do both - native iOS app AND a Crestron module. My Meridian dealer talked about a recent install of an MC600 where they did exactly that. Most of the family members just use the Crestron integrated control module while the dad may jump into the iPad app now and then. This could easily be something I do, especially since mnost hardware pieces have that iOS control piece built-in (Aqualink would require additional hardware for the web/iOS interface, but that's the only one I've seen so far that would need a hardware add-on - Sooloos no longer needs a hardware bridge for Crestron integration). Also, there's no reason why I couldn't choose to start with the iOS app for a device and then pay to add the more direct Crestron control later. As long as what I'm doing with the app doesn't mess up the expected behavior for the Crestron control scheme, this could work well. For instance, I know that I'm the only one who will use the DirecTV iPad app, and that's totally ok. So, those receivers will have Crestron integration and I can jump into the app when I want to.

6 - I'm going to go through lots of potentials with my installer to work up a proposal that almost certainly includes more than I want to do right now. This way, I'd have a feel for where the system can go - and at what cost.

7 - I'm open to solutions that make things easier for the family, while relegating more complex or tweakable sources to my use only. The latter could be accomplished in a number of ways, including making some sources local only, isolated for use only in certain zones, or simply something that the other family members just choose not to use. As such, I am checking out the Autonomic solutions. I can see how this would be useful - I just want to dig into the details of how it works, etc.