minraise preflop:
-flags your hand as a likely big pair
-gives opponent odds to continue under the assumption that he needs to get lucky to crack a big pair
-creates a pot size that commits you in most non-overcard situations
For these reasons, a minraise gives your opponent a $25 shot at taking your stack. On the flip side, I would think it creates more fold equity because of the monster it reps. I would probably be more inclined to make the minraise with a hand like AK or 87s that desires some postflop fold equity, since it will miss so often (and since it misses you won't offer full implied odds to take your stack). With the big pocket pair, you want postflop action, but when you get it how often is your hand any good?
If your goal was isolation, then a $70 3-bet will also work
You want to discuss villain's line:
Flop: Bets to 3-bet all-in. Since he expects you to have a big overpair, he expects you to raise now and commit your chips. You do not, so perhaps he puts you on AK.
Turn: No sense in betting if you were just taking one off with AK. He gives you a chance at a free card. You bet a small amount which could be an overpair, but perhaps he thinks you will fold to a c/r here, sensing you've been trapped. He calls and plans to donk the river no matter what.
River: Card changes nothing. If you felt you were good on the turn, you will call now for certain since his line represents a whiffed draw. OTOH you might check behind with an overpair and you might make a hero call with AK/AQ.
Now, taking his actions and mapping them back to exactly this narrative of motives is probably impossible. Because you could just as easily map back to a hand like QJ:
Flop: tries to buy the pot....oops didn't work
Turn: better check and call so I don't put my stack in with a draw
River: let's see if I can rep an oddly played set or push this scared money off his hand.
Part of the problem with the minraise is you can't discount crappy hands like QJ.