I'll give it a try based on my experiences
1- Yes
2- Yes but around 1980 the fittings were changed to metric and a set of Lee adapters (
https://leepowersteering.com/collect...sae-conversion )may be needed depending on the year of your PS pump and hoses.
3- In 88 they changed the body style except for Suburbans C-30 and Blazers which still used the old squarebody style until around 91.
4- Not familiar with the BBC bracketry
5- I would get a new one anyway
6- Once you get a PS pump on your block, it depends on the hoses and the year of your box, 80 and newer, metric fittings
7- 8-9-Yes- a PS pitman arm, I would stick to 87 and earlier to avoid confusion when buying parts.
Hope some of this helps,Good Luck