Questions for other HicTop 3DP-11 owners

So I recently received and built my 3DP-11 kit and using the included filament have successfully printed off 5 objects. and I have a series of questions to ask which I will split into groups:
Group 1: General maintenance and repair

• What nozzles should I buy?

• What endstop switches should I get?

• What belts should I buy?

• What thermocouples should I buy?

• Any other Hot End parts?

• Any Servo motor replacements?]

• If the control board or LCD board were to fail what should I get to replace them?]

Group 2: Filament Choice

• What Filament brands work well?

• Any special precautions I should take with any filaments?

• What bed and hot end temperature combinations work well with your suggested filaments?

Group 3: Upgrade paths

• Has anybody gotten Octopi to work with the 3DP-11?

• I've been reading about lead screws should I replace the threaded rods that come with the kit using them?

• Should I build en enclosure?

• Are there any parts that I can print to upgrade the printer? Do I have to try to design them? (like something to better hold the Z axis guide rod than that thin metal plate)

• Any Hotends that I should use instead of the one that comes with the kit

• Any Other upgrades?

Sorry for the wall of text but this is my first 3d printer and I am loving it, I just want to know everything I can.