The way I tested the split was to have around 24 tracks in the project. I first put C4 in "All Tracks" mode (out of Chan Strip). Now the display shows me track 1 - track 24. Then I press the split. The display 1 now shows track 1-8, Display 2 shows 1-8, display 3 shows 9-16, and display 4 shows 17-24. clicking split again puts it in 2/2 mode with upper 2 displays showing tracks 1-16 and lower 2 displays also showing 1-16. Now I "Select Lower". Then press ChanStrip. This puts the lower 2 displays in Chanstrip mode while the upper displays are still in track mode.
Hope this helps you get started with understanding the split function.
Yes. This is something I have also noticed. That is possibly because I "was" sending a note on (vel 7F) and a note on (Vel 0) in quick succession. The 1.03 template is only sending 7F. That may be the reason you dont have to hold the ChanStrip button.Assignment buttons need to be pressed for a short moment. Very short presses are not registered by Logic
Display part is actually very easy (once you understand it). You have 55 chars to display. You get a start character and a length of the string. You just need to figure out which of the 55 chars you have to replace when you get the message . So if you get start as 0 and length as 7, it means you have to replace chars 0-6 on the display.
**Edit - Just tested your ver 1.02p. For btnChanStrip and btnFunction, remove the "On Target". Make it Object Target = None. That will slove the problem of having to keep the button depressed for some time. I also checked the code changes made to btnSplit. You need to keep the updateSplitState function. That is what reacts to returning messages from the DAW and changes the state of the C4.