There are more experienced people on here- but I will leave my 2 cents worth!
I added a AMULET quick connect on mine-this is a manual unit, but works well.
You can add a thumb easily by using a solenoid activated valve to use the side boom shift function for the thumb.
There is also an extra spool valve location on the rear valve bank - but getting a spool and the rest of what’s needed to make it pilot controlled will be expensive and a bit more complex. This location from the factory would normally be used to run thumbs or hammers using another pilot valve on the floor on the left side of the cab.
Surprisingly so far I have been able to get all the parts I needed from Komstsu, just pricey and not always in stock. Also found a few other places like AMS that have some parts for it.
Mine was a bit rough when I got it, but it is a really nice running machine now.
Good luck!