That may have been from a post of mine where you heard talk of a FMA/RMA hybrid. I was saying that was the case when I first got into Systema. Though it certainly isn't the case now.
If you bring RMA into your FMA, that's okay (aside from purity in lineage issues), and if you make use of your FMA knowledge when learning RMA that's okay to.
In RMA we look to bring out what is in you, and strip away that which isn't. If certain FMA things have really become part of you, then they will likely help your RMA. The dangerous area is when you try to "impose" FMA concepts and prejudice (I don't mean that in a bad way), onto your study of RMA.
Make sure not to limit your exploration of RMA because of predefined ideas of right and wrong that came into your head from FMA. In my life an example of this from my life was using shoulders to defend with. When I first started, I sort of that that ridiculous. I was prejudiced and it delayed my progress. Once I stopped resisting the idea, it became easier for me to use my shoulders than my hands.
The other trap to watch out for is "looking for things you know". There is a tendency to try and find that Kali takedown you know already, rather than just exploring and finding new things.
Be careful of those 2 things, and likely the FMA will benefit your training. Fall prey to those traps, and the FMA training will hinder your progress.
Concerning Al... I met him briefly at the Denver gathering 3 years ago, but didn't have the opportunity to train with him. I do remember enjoying his posts on the eskrima digest back when I was subscriber.
Good luck with the exploration!
Arthur