Yes, I was a patient of Dr del Castillo! I didn't answer earlier because I really don't have a lot of answers for you. But I had a successful VBAC in October

I was not a patient of his during my early pg - I switched providers at 22weeks - so I don't know what he routinely does during early pg. But both of my old OBs did early u/s too, so that sounds normal to me.... plus I had IUIs to get pg, so I'd had, oh, 5 u/s before I ever went to an OB at 9weeks.
I'm pretty sure that the pelvic exam is a pap smear. I had one at the start of both my pg's, but not when I switched to Dr DC.
As for how many u/s... well, again I don't think I have a good answer for you. I didn't see him until 22 weeks and by that point I'd had a ton of u/s already - from the infertility docs, and then I lost a twin and had extra u/s to check on my little survivor which I could not have done without and maintained my sanity. And then I got GD so Dr DC wanted to do extra u/s to keep a closer eye on size. And at 37 or 38 weeks I started having biophysical profiles done weekly, so that's a lot of u/s. But I never had an issue with u/s so I don't know how many of those I could have skipped...
He seems like a pretty reasonable guy and is willing to discuss most things, so I imagine if you feel strongly about avoiding/minimizing certain things that he would go for it.
OK, here's the embarrassing part of my answer. I never discussed monitoring with him. I had no birth plan. I had everything so planned out with my first, that my only plan was to make it a better birth and I really buried my head in the sand a bit on this topic.

When I got to the hospital, Dr DC was on vacation (I knew this ahead of time, he told me his vacation dates at my very first appt with him, his vacation started the day after my due date.). I also had GD. I was dealing with one of his backups, who says he does vbacs but didn't want to do one on me since I had GD, was overdue, and frankly I think just because it was 11pm on a Sunday night and he wanted to go home to bed. (I think mediocre backups are Dr DC's biggest drawback as far as vbacs go). And so I didn't even pushback against the monitoring. In the early stages I paced around the bed, sat on the birthing ball, and make frequent long trips to the bathroom, but I was mostly on the monitor. At 6am I asked for an epidural, Dr DC got there at 7am as they were placing the epi. So I don't know what he would have said about the monitoring.
I hope some of that helps though I don't have many answers that you're looking for. I did like him, I'm glad I chose him. Oh, I also want to add that there were several points through my day of laboring that if he had suggested a c/s I would have gone with it. He never did. He had more patience than I did, and I'm very glad that he did.
ETA: Oh, the other thing I liked about him. The first time I met him I was fully clothed and in his office, not an exam room, so I felt able to talk/ask questions as much as I needed before I went into an exam room. I hate meeting a new doctor sitting there in a paper gown.
- Jena