DaVinci jr. 1.0 - a lot of questions.

Hi!

I'm not new in g-codes, but now I got my first 3D printer. So, as expected, I have a lot of questions.

The machine is DaVinci jr. 1.0, second hand, in mint condition, firmware 1.0.4. With some filament (PLA), which is in not so good condition due to it's age.

Now the printer works with this chain. SolidWorks -> save to STL -> Cura - save .gcode -> simulation with CAMotics -> miniMoverUI 0.9.5. to convert G to 3W -> sdcard to transfer the files to the printer.

Questions:
1. Can I read somewhere stock versions history and what is changed from one to the next?
2. Z-offset in this firmware version is in steps of 0.1mm. Is the version with improved resolution?
3. Some service manual? I'll be happy to adjust zero point to center of the table and Z to just touch the bed. Permanently.
4. I'm looking for COM port driver, which as I see, is different installation part of some first releases of XYZ software.
5. Very helpful for me will be if I can see absolute position of the head on the LCD. Some of firmware's can do this? In monitor mode position of the head will be welcome too, not only the temperature.
6. Heating bed for this model? Layer fan too? How to add I know, but I'd like to connect to the existing PCB control them via some M-codes. Any working mod for this?
7. V1, V2, V3 communication protocol? How to know which FW version with which protocol is paired? Probably in the future time I'll try to prepare a control panel to the printer, connected via USB. Direct entering G-codes is one great feature for the old school.

For now is enough. Anyone, who has information, ideas etc. is welcome to write here.