Presumably you wouldn't need a long pin. Two short ones which dropped through the the top of the bracket would do the same job....
Yes can't see why not - presumably it's just a bit more fiddler
Could be, but may be easier to source......
Just a thought.
Yes agree
Although getting two brass or stainless rods at a certain diameter cut to length then having both ends threaded using a die
4 stainless acorn nuts - one glued at one end of each won't be a huge job