The short answer is it isn't remotely reliable to assume the RBN will pass on a CQ SOTA call. RBNHole makes no assumptions about the type of CQ that arrives, as there's no real guarantee what type it is anyway.
I wasn't around when those debates were happening, but RBNHole essentially is a direct callsign match. I suppose it'd be easy enough to add in checks for /P stations as well via another query against the RBN spots. RBNGate used to scrape the SOTA twitter feed to get the latest spots, and used those spots as a lockout for any RBNGate spots. If there was an existing spot for an RBN activator on the same band, then RBNGate would not place a spot. I feel dirty enough screen-scraping the alerts page, I'm willing to wait for the SOTA API to pull in Spot details before I implement such a feature. The main advantage of that is dealing with skimmers that use a different offset to you and spot you 100Hz above or below.
You're making an assumption here that is false: that the RBN knows anything about summits and can therefore pass it to RBNHole/RBNGate. The only way of determining summits is by checking which alert is within the window. This means if you're late to the summit, sometimes you'll get misspotted, and sometimes, if you stay too long and enter the window for your next summit, you'll get misspotted. So, no, the wildcard isn't applied, as RBNHole isn't psychic. It will actually post a summit ID with the wildcard in place - GM/SS-??? or G/WB-XXX or whatever you've chosen. If SOTAWatch accepts it, it appears on the main screen; if not, it disappears.
Regarding the duplicate spot handling, RBNHole will not repost for a period of approximately 10 minutes, unless there's a band change or a frequency change of more than a certain amount of kHz. I think it's +/- 1kHz, but there was some discussion early on. It might be 2.5kHz. I could look at the code, but that would be being diligent, so I prefer to guess from memory.
Fundamentally, RBNHole and RBNGate are both fairly dumb translators of the RBN feed into some semblance of divination regarding what's actually happening on the summits. If there's an RBN spot within the window of an existing alert that matches on callsign only, then a spot will placed on SOTAWatch for the closest alerted time, unless we've already spotted in the past 10 minutes within X kHz of the existing frequency.