Hi SWallace -
I think the majorty of women on here are getting married at the Royal, so I'm not sure how it would work to just schedule the other events separately. That said, in the wedding price packages there are fees listed for private receptions, and based on an earlier conversation I had with one of the WCs, if you're looking to do a welcome dinner, cocktail hour, and/or rehearsal dinner, you'd just pay those prices (e.g. $10pp for cocktail hour, $15pp for semi-private dinner, 15 people max, or $30 pp for a private dinner with minimum of 20 people). However, because you're not booking a wedding package, I'm not sure if that will impact the cost. I believe you're also able to eat together in any of the restaurants at anytime if you have fewer than 15 people - they'll just push tables together for you. The wedding coordinators are assigned once people book their ceremonies, so you may instead try calling the 800 number on the website and finding an appropriate contact for the event scheduling that way.
As far as the salon goes, some people have had good experiences, some just ok, and some not so good. The general concensus seems to be that if you have a pretty specific idea of what you want, they'll likely be able to mimic the photos you bring. I think they also have a book of bridal hair styles to choose from. Makeup-wise, I don't know if I'd trust their choice of foundation (there's another forum on here about the right makeup for pictures), and I know some brides have brought their own makeup and paid the salon to apply it for them. There's also a MAC counter right around the corner from the hotel, and they'll do a trial for a $70 purchase and day-of makeup for another $100. It's pricy, but at least you get makeup that you can keep. Finally some brides are paying for outside people to come do their hair and makeup, but it generally costs around $350 and then you may have a $350 outside vendor fee on top of that (some brides were charged, others were not). All in all, I think you'd be fine with the Royal spa, provided you knew what you were looking for beforehand.
Best of luck, and please respond if you have any additional questions.