Thanks for the clarification on my bad example. What I was really trying to emphasize was that you only evaluate the text one time.
I can't find anywhere in the rules where the word "AND" means you do one action first. In the English language, AND is not serial, it is parallel. As far as I'm concerned, any LOTR cards that use AND are saying two things happen at the same time, such as "Make a companion strength +2 AND damage +1." There are other cards that use "THEN" to indicate that you do two actions in series (such as
Durability 12C4). If there weren't any cards that used the word "THEN" I would probably be inclined to agree with you. But there are cards that use "THEN" and this is not one of them.
From a different form of evaluation, if you are taking the snapshot when the fellowship moves, and Merry has 5 resistance, then he is a member of the group "each character who has resistance 5 or more" and therefore not "each other character" (they are mutually exclusive). If you apply the text in a serial manner, you heal each character who has resistance 5 or more; then when you apply the second part of the text, you are only considering "each other character" that you haven't already healed. So it still shouldn't matter if Merry's resistance was changed because he was already part of the first group of characters.
Without any references in the rules, I think we are just going to be arguing personal interpretations.