If I was looking at augers, or post pounders, I’d look for skid steer units. I have The universal skid steer quick attach on the FEL. And mounting to the FEL I could generate down force, unlike the three point.
Your T25 has the same mount system. So, I recommend looking inn that direction. Bigger rental yards frequently have skid steer attachments that they never have for tractors. I’m in a small town, and the local yard has, augers, pole pounders, and pole vibrators. It is owned by a large local contractor, who buys equipment for projects, and then adds to to the rental inventory, when he doesn’t need it. I tried for years to convince him to get a rock bucket, with no luck. After I finally bought mine, he looked at it for a few minutes, and decided to order two. He is installing miles of phone ducts, and the backfill has to be 3-inch minus, and the native has about 60% rock from 3 inches up to 18-inches. He figured out what I had trying to tell him, that if they can screen onsite, it will cut their import by 40%. Which covers the cost of having the bucket on the skid steer he already has onsite, and moving material from the trench to the bucket with the mini-ex.
You would also need to add a third forward hydraulic circuit. TYM makes a very clean third forward kit for your loader. The third forward lets you run grapples, etc. and is worth the money. If I could still get the TYM factory kit for the third forward on my tractor/loader, I would be installing it, instead of looking for piping components to add a splitter. One of the guys on YouTube with the T25 has a good video on installing the factory kit on his machine.