I am curious about number 2 and 4? I know newline (camburg stole their goemtry) SI and such mount the lowers off the front of the links to move instant center infront of the truck, and not in the middle... When i linked my ranger back in the day, i looked long and hard at your geometry and SI geometry... I decided to split the difference. lol My thought was instant center out in front would keep the truck planted in the whoops, which to me seemed to ride good, but also didnt want to put all the torsional load of the rear end on the uppers like you mentioned in 2. I think i put mine like 20-30% off the bottom... Also my thought was off the bottom means the links sit lower and more apt to hit shit.
I will also say depending on the truck you link, the upper inner mounts will likely only be able to go in 1 location. I know on rangers you can only get them so high because of frame and cab, on the toyota i linked we put the mounts right ontop of the frame. Both of these trucks had the front lower mounts just below the frame. both seemed to work decent. I found most people get so scared about the geometry, but in reality its going to be a million times better than leaf springs no matter which goemetry ques you take.