Looks like it could also be a 'spring over' using that top hole, which would allow the hairpin flange to be bent.
Have you mocked up all the steering too? These tend to require a bunch of fitting to get everything to work well and look right. Try to get it all at least mocked up and stand back and take a look before making changes.
I would prefer to bend something to correct that gap, rather than hang to rear joint 3 inches out from the frame.
Was the other tab on the top of the axle for a shock mount? Possibly a lever or friction style?
BTW, I haven't gone back and looked at your previous posts, so I don't know your level of expertise. Please know that those nylock nuts on the spring hanger are supposed to be used only once or a couple times.
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