I guess if you're fine with having one battery, it would be alright. I'm not a fan of their chain tensioner, I have experience with them on a corded dolmar, they are terrible.
Get one so we don't gave to.
No, it's a 3:1, because you are the one pulling on the end, making the upper pulley a moving one. It's the same system as RADS.
The Rollclip is intended for life support, the manual shows it being used on a bridge to connect your climbing system. It's only 20kN though, so maybe under your...
Here in Germany chains are standard on playground swings. Probably mainly for longevity and tamperproofing reasons. But I know regulations are quite strict for potential spots one could injure themselves at.
Why the Treecore or the Tree access? What about them do you like? I've worn the Treecore, not very comfortable for me, but maybe it wasn't adjusted properly. I'm 6', also skinny. I had the same issue you had with the backpad on the Tree Austria. I do like the modularity of the Treecore though...
That depends on the diameter of your rope. On my 12mm 16 strand there is much less load on the hitch with a wrench, on drenaline there is a only little bit less than in MRS for me. But always less than MRS. I don't climb on 11mm or something like that though.