The wiring harness was difficult and really intimidating but if you take your time you can get thru it. My suggested tips:
1) Watch all the videos and take notes and wall through the steps before actually cutting wires out.
2) Watch the old archived videos too as sometimes they have different options or connectors
3) get the wiring and connector diagrams from alldata.com, they help answer the questions you may have from the videos or will confirm the video instructions
4) when in doubt, keep it rather than cut it, you can always cut it later when you're sure
5) I echo the plywood layout recommendation
I took my time with this process and was pretty meticulous but I think it was worth it.
As to your questions regarding the ABS and airbag connectors:
ABS- most of those wires can be removed, however your LAN wires almost certainly go through there so check where you will need to route them before cutting the other end. The wires from the wheel speed sensors can definitely be removed. Ultimately the whole connector will be removed so you can cut the wires and then label the ones you're still unsure of with there connector location.
Airbag- I'm 98٪ confident they will all be removed, I think the videos cover it pretty well.
Good luck!