AtomStack sent us one of their units, I just received it a few days ago and so far we have just assembled it, but not yet run it. I did already take it apart though 
so I know that the board in there does look very similar to the DLC board.
It has $30 and $32 GRBL settings set correctly out of the box so it can be used with LightBurn immediately without any settings changes.
However, I tried changing some settings and noticed they did not persist across a power cycle of the machine. When I power it on, I notice an EEPROM error in Console along with the $$ settings list. Can you confirm if you see this EEPROM error in Console also?
It has the normal Atmega328p chipset - it should have EEPROM. Either they butchered it in firmware, or it’s a fell of the truck kind of chip.
I need to get some more hands on experience with the machine as is before I can flash a new GRBL build onto it and hopefully that fixes the EEPROM issue (if my theory that they butchered it in firmware is correct) and allows homing setup.
Also, please show me how you have connected the limit switches. Actually, if you can provide nice pics of all this, I can use them in the guide I am going to write and it will save me some time.
I don’t have answers for your other questions yet. Pics will help, I need to see what you’re doing.
Thanks!