I can't believe I didn't set up this thread to 'notify' me of new posts.
I've been doing plenty more research on this and it actually doesn't seem too bad. Your library seems like it would do the heavy lifting, it's just a matter of adding the actual 'meat and potatoes' of the code for what I want it to do.
I was worried briefly that I wouldn't be able to use an LCD at the same time as MIDI due to pin conflicts, but after looking at stuff that doesn't seem to be the case. And since I'm going to be using a Mega, I don't think I'll run into pin shortage.
Where I'm starting to second think things is using buttons as the sole navigating/input method. If I have 6 main things that I can add a number of functions to, it would take forever to change things on the fly. Granted that this could be circumvented by having a handful of presets saved for most of the settings I would want to use (including a "do nothing" one). Ideally I would have some immediate real-time control of certain parameters with an encoder(s), but how this folds in with an LCD/menu in terms of code/menu is something else.
Thinking on a bit further I think with enough presets I wouldn't need real-time control (I could just make new types of presets ahead of time). I'm assuming the EEPROM addition to your shield would allow for storing sets of data in terms of memory and menu/display functions?
Would different LCDs work with your shield? Like this one:
I considered just going with an LCD "raw", but having the navigation buttons on your shield would make things much simpler in terms of hardware/software.
Then there is the problem of incorporating it into an enclosure (the old "square hole" problem, and little PCB buttons with hats on them sticking through the top).