I went to bed early last night and am still catching up on this. The above is likely correct, though again, Puerto Rico is its own thing. The following assumes that Puerto Rican authorities have agreed to probation. I haven't seen that stated by them.
If it's anything like standard US practice, SA will have to plead in open court. The judge can, and most likely will in such a prominent case, question him, on the subjects of whether the plea is knowing, voluntary, and intelligent. It is really up to the judge how far to go on this. It can be very pro forma, in, out, rubber stamp plea deal. But this circumstance of pleading guilty while not admitting to the allegations, I'm hoping will cause the judge to ask a few more searching questions like "What did you do to cause you to plead guilty?" and so forth. Very much depends on the judge, at least in the US. Puerto Rico may have its own ways.
The reason why he's not admitting to the allegations is almost certainly civil liability. RCCI could sue him or else join him in the current lawsuit as a third-party defendant, liable for anything they are liable for. That does not mean that successful plaintiffs would be out of luck, it just means that RCCI could try to recover any payout from him. If he's admitted to the allegations, that would make a civil defense very difficult.
As to whether the judge can put him in jail anyway, the papers say this is a "plea deal". The judge can accept or reject it, but if rejected the case would continue, possibly before a different judge. A "plea with a recommendation" doesn't bind the judge in any way.