A: The ribbon cables on the X1 are the conduit from your mainboard to the visible components of your printer. If something is not working, there's a good chance your ribbon cable is either not plugged into the connector fully, or the cable is no good. Always check the easier thing first.
A: The WiFi on the X1 is not usable. It may show up as a network device but attempts at making it useful have failed. If you want to communicate with your printer wirelessly, get a different screen or implement Octoprint via a Raspberry Pi.
A: For whatever reason, you have to disconnect the stock screen in order for Arduino IDE to fully upload to your printer's mainboard. Some times people get lucky and it works without disconnecting anything, but most of the time it fails. If your upload keeps failing, disconnect your screen before uploading. While you're in there, some people added a simple switch to simplify the process.
A: Yes, and no. The stock heat break is lined with PTFE to help filament flow to your hot end smoothly. The stock setup is optimized to print filament under 220c, like PLA. You may be able to print at a higher temp, but it's only a matter of time before you start getting issues like under-extrusion and clogging. The cheapest way to start printing high temp filament reliably is to change your stock heat break with an all-metal one. The more you spend changing out your stock extruder, like moving to Hemera, the better your prints will be and the more reliable.
A: Josh Pielemeier - “You need to first get your stock printer printing to the best of your ability with no mods. Some people will say to print strain relief mods to begin with for the bed power cable and ribbon cables, but I never did and have not had any issues. The last thing you want to do is start taking your new printer apart looking to improve things that you don't have a baseline to compare to. Every printer is different. The only thing I would suggest for PETG is an all metal heatbreak and nozzle so you don't have to worry about melting the PTFE tube in the stock heat break. That said, you should really try to print with PLA to begin with and get the feel for the machine. Calvin Witt is a Youtuber that has some upgrade videos for the X1. Check him out when you decide to start upgrading.”