1 - biggest concern I believe would be the rubber/silicone insulator and/or the o-rings. the metal parts would probably outlast both. there are replacements insulators/o-rings available to extend the life of heads, if needed.
such as:
O-Rings for the Kanger Protank base.
2 - lots of options to choose from. searching for the perfect wick could be a long journey. I find that silica is a good performer but have recently moved to cotton and haven't looked back. I have no experience with the other types of wicks, ie: hemp, ceramic, steel mesh, ekowool, wire rope, cotton yarn, etc....
I started with silica, it sounded like it would be easier to reproduce a build once I had it right. but even tho cotton took a little more practice, I find that it performs a lot better. Best way to find out IMO is to play around with all the options until you find your sweet spot.
same goes for wire. lots of options, experimenting is the only way to be sure of what you prefer. I'm using 28ga Kanthal A-1 most of the time, for mini/micro coils. I also have 30ga and 32ga to play around. A few different sized blunt needle tips or drill bits is not a requirement, but I find it's nice to have them around, so that I can follow tutorials with the same specs that was used for that build.
a few places you can get supplies from:
Rebuildable Supplies - Kidney Puncher
Lightning Vapes LLC @ Amazon.com
Kanthal Wire 30 Gauge RW0105 - 25 FT 0.1oz Series A-1 Resistance AWG
CVS 100% Cotton Triple Size Organic Cotton Balls - CVS pharmacy
3 - with botton coil clearos, such as the protanks/evods, 'flavor wicks' are used on top of the coils, to help seal the chamber and to prevent leaks/flooding. depending on the thickness of the juice, flavor wicks are sometimes removed completely. It's not really about the material (silica), flavor wicks can also be made of cotton or hemp or ekowool, etc... even mix and match, ie: silica wick + cotton flavor wick, works fine.
basically it's just one or two small pieces of wick, sitting on top of the coil, so that it fills the grooves at the side of the head. (bellow the larger silicone grommet). as seen bellow:
a few other things that didn't normally sit as close to me before, and that you might find useful to have in your toolbox: a small torch lighter, a digital multimeter or ohm tester(required IMO), magnifying glass/table lamp, tweezers, threading needle, nail clippers.
so, your conclusion is pretty much spot on. many ways to do it, only way you'll find out which works best for you is ...start testing!
With a little bit of wick and wire you can build your first few coils, and decide if you want to invest further in your search.
anyway, just some ramblings from a novice builder that was a little overwhelmed at first too with all the info, but that really enjoys tinkering with coils.
I hope this helps, good luck!