In Alamy, there are 3 options, RF, L and L protected, so my understanding is if you choose L, then you can upload the same photo to other agency as a RM as well, is it right?
And one more question, can I remove all logos of a RM photo to Alamy again as a RF photo?
I believe L and L protected are now, or are shortly about to be merged into RM.
RM is not exclusive to Alamy, but if submitting over multiple sites, make sure your record keeping is precise and always up to date. For example, should a buyer wish exclusive rights on an image, you'd need to know whether the same image, or a sister/similar, has sold from another agency to the same market they're hoping to buy exclusive rights for.
Your RM/RF question is interesting, but I don't know the answer. Hopefully someone else
knows the answer, as opposed to speculating.