How would one pronounce this; with an almost mute h?
No, with an aspirated “h”, just as with “an heroic”.
Minimé, per h aspiratam sonitur, sicut etiam “an heroic”.
Is “an heroic” still normal? What about an universal? I suppose u is pronounced without a j?
“An higher” is rather archaic, “an heroic” not ususual, but “an universal” (without j) would be eccentric these days, I would say.
Archaicius primum, non alienum secundum, aberratio hodie tertium, dicam.