New (to Me) 2010 Thunderbird, Got Some Questions

I just picked up a 2010 Thunderbird with 60k on the clock for $2500. Recent engine rebuild about 1000 miles ago, and all service documentation since day 1. Also a different seat with a backrest, which I much prefer over the stock seat and pillion. Just nice peace of mind having something to catch me when let the torque loose lol. It's a little heavier than I'd like (I'm coming from sportbikes), and the tank is pretty wide (I was actually looking for something like a Speedmaster or Yamaha Bolt, slim and sporty), but I'm getting used to it. I was originally worried about the engine noises, but they really don't bother me that much. I have been noticing some other things about the bike, that I just have some questions about.

These seem to love cruising around or a little over 3k RPM. Though I've noticed some slight stumbling while maintaining speed under 3k. Almost feels like it's going to start to running out of gas, but she just keeps on chuggin. I'm guessing this is just a regular thing with these engines? It runs great otherwise, and I think I've read something about keeping them above 3k, but that might've been for Victories or one of the other bikes I was considering.

One of the big things I think I've already got figure out, but haven't had time to check yet. It pulls the left slightly, not noticeable while riding, only when letting go of the bars at highways it veers off. I think this is probably just the rear wheel adjustment being a little off. Open to other ideas or things to check though, tires look brand new and are properly inflated.

The other major thing, I cannot figure out for the life of me. Occasionally, and I really can't figure out how to reproduce this, other than it being most noticeable at low speeds and doing some sort of maneuver like entering/exiting parking lot, etc. Sometimes I hear some sort of weird squeaking or scraping sound. To get the obvious thing out first, I'm not scraping pegs or anything. Any ideas what this could be? Is it just another normal odd sound these make?

Another thing I've noticed a couple times, is occasionally on the highway I'll hear a faint buzzing sound for a few seconds. Kind of reminds me of the sound the fuel pump makes when it's priming, but it's to tell exactly through a helmet plus wind, exhaust, etc.

Any info on these would great. This thing is a beast, and almost matches my Mustang.

 

That's what me and buddy figure it was. Took a look and the back tire was way off. Seems to go fairly straight now, maybe a little more adjustment. Also haven't noticed the squeak much, if at all, like you said. I also think the surging issue is the MAP tube I've read about. I gave them a wiggle and it seems to be alot better. Still happens occasionally though.

Also, as I was looking through the service docs I received with it, I was surprised to find it had the 1700cc big bore kit installed by the dealership. Should have been obvious since it has the 104ci plate on the trans cover, but I just assumed 104ci was 1600ccs, never felt the need to check it. Guy I bought it from bought it from the original owner and only had it for a few weeks, never even transferred the title, so I'm technically the second owner. The original owner kept pretty much every bit of paperwork. I even got his original purchase agreement from the dealership (he traded in an '09 Speed Triple). Also got the invoices for all the Triumph accessories on/with the bike. There's also a dyno sheet from before/after the big bore kit, showing 83hp and 102ft-lb at the wheel, up from 68/93.