...the rest of the points you've made up until now are at least debatable, with a great many sticking points attributable to possible discrepancies in nomenclature.
But there is no "direct contact" between the springs/shocks & the frame, there are rubber spring isolators between the springs & frame, & every shock absorber I've ever seen has bushings in both ends.
But if what you've done is working for you...![]()