I'm digesting what you are saying, still...
You are correct, it is not long enough to be a 2-to-1. Followed your advice, but instead of a leash snap, I used a pulley to tend the directional Prusik. I'm unsure that I constructed a directional Prusik properly, but I will post a couple pics later. It seemed to work, but before I trust my life to it, I'm going to make 100% sure. The sewn-eye Prusik cord I got sucks; it's a little too stiff at the eyes, which did does weird/annoying things in some situations, it seems like.
The girth hitched tail actually wasn't load bearing since I never used it as a 2-1, so moot point on the hitch walking of the snap, I reckon.
Double wrapping the straps either worked like a boss, or my calves were much more used to the stresses placed on them this time by the spurs - I stayed on the tree for over 2hrs, more or less, this trip.
Running bowline for anchoring the moveable the in point and advancing it with me worked fine. I don't foresee this being an issue. I loosened my lanyard and flip line and tested my weight on it, and it cinched up and held around the trunk perfectly
The hip D-rings seemed a little crowded at first, with both a flipping and a lanyard anchored on them, but I flipped one around so they adjusted on opposite sides, and that seemed to help. Not sure if it would have been an actual problem anyway, having them adjust on the same side.
Being tied in 3 ways really made me feel pretty secure. Was able to go up about 30' without feeling the slightest amount of nerves. Tried some maneuvering, like circumnavigating the trunk; worked fine.
The tree was a little larger this time, as compared to last. Probably about 18" diameter. And it definitely helped having my feet farmer out towards the sides. Didn't gaff out once.
As to my jackleg rope situation...
Got the hitchhiker 2 in the mail. Decided to try it on 1/2" ProMaster. That seemed to work well also. It supported my weight without a problem and allowed me to descend and 'ascend' (which was really just me moving my body closer to the running bowline loop at the tie in point if I needed to), although it required a little muscle at times, and adjustment of the HH2's friction hitch length. However, I'd rather it be slow and hard to release than super duper easy, if I have to err one way. I'll get a for-real climbing line however to use with this. But in the mean time, this SEEMS to with with the hitchhiker for the intended purpose (emergency way out of the tree instead of having to back down it on spurs).