Wrong:
1) first stage 8.1 (12. December) contains all fixes, Warfront, Isles, Invasions, vendors and campaign (this one will be timegated, I heard it will probably have 4 parts)
2) second stage of 8.1 (January) will contain new raid, seasons 2 of M+ and PVP and fifth azerite ring
3) 8.1.5 is separate thing: it will have all that they annouced on Blizzcon (including Zandalari/Kul Tiran) + likely Naga world quests (although they may start just before 8.2 when we'll go to Nazjatar), Crucible of Storms and questline leading to that raid. No idea when it will come out, my guess is March (and PTR 1-2 weeks after raid).
Nothing stops you from that. Just avoid sites discussing upcoming stuff from public testing. Or you rather want 0 public testing and even more bugs than in 8.0?