My personal assessment and attributions are to categorize them as F-274a variants.
Inasmuch as the F-274a is considered to actually be a 6 over higher 6, unlike the F-282a which is clearly a 6 over 8, I consider all the various incarnations of 6 over 6 to be F-274a variants.
Again, these are only my thoughts and how I have classified them in my collection..