To be clear, if your remote works great under 5.0.3, it should work great under 5.0.5. My problem with remotes was consistent under *all* versions. Once I implemented @MikeD's recommended fix, it would work just as well under any version.
In short, there is no issue in upgrading, not in my experience. In fact, I noticed that my CPU usage during some videos went down in the 5.0.5 version (the main difference here being the 14.2 Kodi BETA vs 5.0.3 which as the 4.1 Kodi Release).
Regarding the H -vs- B boxes, as long as your remotes have been interchangeable, you are not suffering from the same issue I had raised earlier, so I would not worry about a thing in upgrading.
About the CEC issue, if you look up above, I posted a solution to this. My solution was far a Sharp TV, but once you find your Samsung code, your solution will work identical. It's very easy, basically just a single line with some XML tags around it!
Good luck!
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