Pretty spot on but I'd add - don't buy Nuprol batteries, look at Turnigy, Vapex or Giant Power https://www.componentshop.co.uk/batteries/airsoft/li-po-packs.html
Tracer - standard threading on almost all brands of airsoft barrels is 14mm Counter Clockwise (left hand thread) so pretty much all the things that screw onto airsoft barrels are 14mm CCW too.
Foregrip - as far as rail attachments go, make sure the one you get is RIS compatible (or mentions "picatinny" or "Weaver" or 22mm rail) and you'll be fine. M-Lok, Keymod et al don't fit the rail you have. As for having one or not, use the gun, work out how you feel comfortable holding it and go from there. Lots of people buy foregrips and end up holding the magwell most of the time AND THAT'S FINE TOO!
Optics - I think we may be confusing Vortex with Vector here. Vortex optics definitely cover having the glass shot out and they don't care how. Vector Optics ARE very good and generally cost less than Vortex (I have several), and they do have a decent lifetime warranty but I'm not sure if they have usage caveats. That said, buy a lens protector and it won't be a problem anyway.
If you're unsure about ANY of it, ask here first - you'll get loads of opinions, granted but better than buying a turd and then getting roasted for it!