If you are not dead set for minis - have you considered humbucking P90s? Not exactly the tone of regular humbuckers, while indeed humbuckers, looking like regular P90s or close but also no routing as with minis.This is just an example, no affiliation or experience with these on my part. https://www.creamery-pickups.co.uk/...90-pickups.html#custom-hum-cancelling-designs
Somebody with experience might chime in, but my guess these might be better suited for a LP than minis, and give more individual tonal signature, while not overlapping with the ones you already have, tone-wise.
Mini's for me. Actually i have Phat Cats in my viking deluxe Tremar and really love those. Been thinking of maybe using p94 in another lp. Or take the Phat Cats out of the Hagstrom .....oh whatever too many ideas.