@Disneylover99 - it didn't pull your quote to reply for some reason!
We had lunch at Sanaa right when it opened, got to the Kidani bus stop around noon - there was already a group there that had been waiting for almost an hour. I think we waited about half an hour more, so around 12:40 I think when we got on the bus. We got to Epcot a full two hours later. We missed our first FP, got to Epcot and sent DH through the bagless line so at least he would make it to our Soarin' FP that was ending at 3:15 while I went through regular bag check (I'd just been in October, and he hadn't been in a year, so i was ok missing out if i had to). It took close to 20 min for me to get through the security line. Luckily the AP entrance was clear once I got to that point so I walked as fast as I could and made it to Soarin' at 3:12.
We stayed until the 6:30 Illuminations was over and left the park...it took like 15/20 min to get back to the resort around 7pm. No traffic that direction! I think you'd be ok later in the evening. People WILL leave MK and Epcot after the first fireworks shows, but around 8:00ish might be ok.
My advice is to be prepared for anything! Everything I read for last year said traffic would be bad after 2pm and to get to a park by 3...well, I think everyone else read that same advice b/c boy oh boy did everyone get to a park by 3! MK was closed at capacity already by about noon, I had a friend texting me updates while I was on the bus, lol! We even saw a lady exit her truck and go to the bathroom behind a monorail support while stuck in traffic. People were driving over the grassy median, and others were leaving a driver in the car and getting out to walk. Everyone on the bus (which was crammed full, standing room only) was having a good time, we were all laughing and joking and making the best of it.
Our current plan is to go to DHS early in the morning on NYE, friendship boat to Epcot, walk to the front and monorail back to TTC and walk back to the Poly. Plan B is to go to MK early and ferry back once it gets out of control. I vowed to never be on a bus again on NYE unless it was first thing in the morning.
**Editing to say, this year could be totally different. According to all of the people on the bus who'd been before, and the locals I met in line for Epcot bag check/security said it hasn't been THAT busy at that point in the day before in their experience. I said I would never go back to WDW over the new year ever again, but here I go the very next year, so I wasn't all that traumatized I guess...although at the time it felt like a nightmare!