Where did you get the ‘flying tiger springs" ?
1) The Konis may have been an attempt to limit axel hop. I had a mid-80’s Thunderbird Turbo Coupe with four shock on the rear axel. Two were horizontal for axel hop control. Is there a brack welded on the fram for the other end of the shock to attach?
2) My guess is it may lower the ride height. It looks like you have more leaves than the stock spring.
3) Original springs had the spring eye off centered closer to the car floor rather than front or back. I think Rootes did it to lower the roll center of the rear axel.
6) The bolt fits into a hole in the middle of the plate the u-bolts bolt to. If you replace make sure it fits throught the hole.