I'm just trying to figure out what airlines(well, and/or hotels) give lifetime rewards at the highest level, since that's commonly by far more lucrative than others, and I'm realizing that not many do?

Doesn't offer Lifetime highest-level:

AA (Only Plat, not Exec Plat)
AS (Only Gold, not Gold 75k)
Delta (only up to Plat, no Diamond)
M&M (? Not sure, I couldn't find it when searching)
Flying Blue (?)
Asia Miles (?)

Offers Lifetime highest-level:
Asiana (500k (!) for Lifetime Diamond Plus, which essentially has the same benefits as Platinum, which can be had for 1MM for Lifetime. All Asiana+*A flights count, or 500 Asiana segments)
AC (3MM for SE+Elite for companion, but AC-flights only, no codeshares/partners)
UA (starting at 3MM for 1k prem, includes companion)
BA (35'000 TP, vs. 1'500 for Gold - 23x, while most other airlines have 10x, so that's mor like 2.3MM for comparison's sake)


which important FFP's am I missing, and is the info above correct? Or am I missing some ways to get e.g. Lifetime AA Exec Plat/AS Lifetime Gold 75k?

Cheers!

I'm too tired to go into all the other different ones that are out there, but BA also offers lifetime Gold Guest List (a subcategory within Gold) at 100,000 tier points.

I'm fairly sure you're correct that AA doesn't offer lifetime Executive Platinum, at least not officially. I dated an EP desk agent some years ago. (FT old-timers may recall seeing us at a couple of Dos). She didn't know of any, either - and we discussed it, since at the time 4MM or 5MM might have been within my eventual grasp if I hadn't changed careers. There may be an unofficial deal via a corporate agreement or two, that sort of thing happens, but nothing that we regular folks can earn in any predictable way by flying a lot.

United offers GS status at 4mm.

I'm not clear on whether "(well, and/or hotels) " includes hotels, but SPG and Marriott both provide top (normal) tier lifetime status (Platinum for both)

And Hilton just added Lifetime Diamond status (Diamond being their top status period, AFAIK). Though unlike the other two, it requires actual paid nights, nothing else. (While Hilton HHonors counts awards nights for annual status, they do not count for lifetime status. While Marriott does not count award nights for any status, they do count rollover nights and credit card nights for both annual and lifetime status.)