Monthly bonuses are based on VIP rank + wager amount counting from the previous month's bonus till the current month. To get the most out of the monthly bonuses, what you can do is to wager a tangible amount. From the reports of other platinum users that I've seen, it's even more rewarding to be a platinum ranked user since it also comes with other benefits. That said, you should give it a shot first and see how it goes.
These names don't really ring a bell with me but I also only follow UFC from time to time.
I didn't get the mail - not sure why. With the new partnerships and promotions, I'm sure stake team is onto something. For anyone (like me) who missed the release, here you go: https://stake.com/marlon-vera