I saw two things on the list that we didn't know, but as of recently we now do.
1) Trials are formed with the sibling to me+ (for 2), which is the prefix pxe+, which like me+ and ay+ cause lenition. So:
mefa'li = 2 direhorses
pxefa'li = 3 direhorses
The trial pronouns also begin with px-.
As a side note, nouns formed via the nominalizing prefix tì- are also subject to lenition. So "3 noble truths" might be rendered as:
2) The honorific/deferential verb infix <uy> is tertiary/class 3 so it comes after any others within the verb and in a multi-syllable verb with no other infixes, it comes in the final position. (e.g.: taron >>> tar<uy>on). In that respect, it is a sibling to <ei> (happy about it) & <äng> (not happy about it) and it cannot coexist or "stack" with either. You must choose which emotion you want to express:
It is always optional and once you have used it to set a tone, you can "step away" in your address or conversation and then optionally come back to it at another point or at the end if you feel the extra emphasis is needed.
This information comes to me from Paul Frommer, Otherwise I would not state it so factually. I always think it's a good idea to explain when we're conjecturing or being "creative" with examples that we clarify that. If you see me NOT doing so, please bring it to my attention and the attention of everyone else.
I think this list of things that "we don't know" is a great idea, and that it will also be encouraging to see those things move either gradually, one by one, or en masse to another column. I'm not one who would be opposed to three columns. (1) Unknown (2) Unattested (3) Incontrovertible.