Hello Sparksteeler, Santa's bringing you a Spark. You've must have been good this year.
1) OTG is not required. I have them but haven't used it in quite a while. The WiFi setup works fine for me but results vary with others.
2) DJI provides instructions on set up. It seems one of the hangups is scanning of the QR code(s) during activation. Just type them in manually as the scanning process is hit or miss. It's a good a idea to place a piece of clear tape and cover the sticker in the
battery compartment as it will wear over time. Better yet, take pictures of the sticker and store in your phone for future use.
3) Yes. You can fly in the house. Make sure you have the prop guards on and the rooms are well lit. The Spark uses a camera on the bottom to determine height indoors as it won't get a GPS lock indoors. Use Tripod mode for slower movements. Stay away from the ceiling as the prop wash may suck it up and skip around like an air hockey puck. Lol.
4) The Homepoint will automatically set. It may take a few minutes to gather up enough satellite information. Be patient, a few pilots take off too early and lose the Spark because it's in Atti-mode. Green light on the controller doesn't mean you're ready to fly, just connected. All of the information will be on the DJI Go4 screen.
Airplane mode disables all incoming data so the phone can concentrate on flying the Spark, you don't need to answer a phone call when flying.
The WiFi on your device is still active so you can connect to the Spark, unless you use an OTG cable, then you can turn the WiFi off.
People think that Airplane mode shuts off the WiFi but it doesn't. Some airlines offer WiFi on the flights for the passengers to use so putting the phone in Airplane mode allows you to use the WiFi and not data streaming while in flight.
5) You will calibrate it when you first use it and only when prompted to do so later by the Go4 app. I think with previous DJI drones it was required but to do it every flight may be asking for trouble.
Do the compass calibration outside away from power lines, pipes, rebar (in concrete), etc. Remove all metal from yourself such as watch, coins, etc.
Some pilots get stuck on step 2 of the IMU calibration because the image on the screen flashes quickly and may not notice to move the aircraft. Pay attention to the DJI logo on the Spark in the setup pictures.
6) DO NOT crash and lose it as it is a fun little "toy".
Read the manual a few times, watch How To YouTube videos, and the Forum is always here to help.
Also, if in the USA you'll need to register it with the
FAA. It cost $5 and takes about 5 minutes.
Welcome to the Forum.