Hey @AdamHLG that’s extremely welcome news - congrats. To answer your questions:
I’m pretty sure the LutronPi (v2) setup completely duplicates all functionality of the LutronPro (v1) setup, so yes: that original RPi and its v1 node server can be decommissioned, along with its associated SmartApp and device handlers.
Of course the new LutronPi SmartApp will create new SmartThings devices (via its own handlers) for all the Lutron devices that its sees on your original bridge. So if you have any of the original devices ‘plugged into’ SmartThings automations, that will have to be re-done in SmartThings. (That’s the pain-in-the-neck part of all this.)
As for the official Caseta integration: I can’t tell you for sure as I’ve never tried it (oddly enough). But if it all it’s doing is providing a lot of duplicated lighting devices, then it can probably be dispensed with. OTH if you find that the official integration is providing something that the LutronPi setup does not: let me know what that is; I’d be very interested! For one thing, it may very likely have more extensive shade control; that wouldn’t surprise me.
Aside from the Pico functionality, you’ll find that the LutronPi (v2) version of the Lutron lighting also provides ramped on and off timing, if you want to use that. (For Pro bridges only)
If you nose around in the Pico device settings (the ‘gear’ icon in the upper right), you’ll find some options like: selecting a ‘favorite’ button that will then appear on the main SmartThings Home screen; whether a button ‘hold’ times out after 6 seconds; whether each button is the standard Push/Hold or instead Push/Repeat or as a Press/Release (like a SmartThings contact). Also, even in the Push modes, the Pico buttons simultaneously act as SmartThings buttons AND contacts, which might be useful for ‘do this while pressed’ automations.
A Pico also has an option to loop its in-app virtual button presses through/to the Lutron bridge and back to SmartThings (so the Lutron bridge thinks the real Pico button was pressed), or to drive SmartThings automations directly (rather than waiting for the Lutron bridge to respond.) That latter mode allows non-Pro bridge Picos to work from virtual app buttons and still also drive SmartThings automations from those app buttons (just not from the real Pico buttons).
Also, if you hadn’t noticed it, in the LutronPi SmartApp setup is an option to turn on notifications. If enabled, this will provide SmartThings notifications when the LutronPi node server goes offline or online and when device complement changes on any of the bridges (e.g. when you add a Lutron device from the Lutron app).
Keep us posted on your progress, if you don’t mind!