Hi Mes,
The "general" temp tollerance for lowlanders that I go by is keep them over 80 days and 65 nights. Now this is fairly general. Just looking at you nep list from your link, most of them look like highlanders, anyway.
The albo, however, is a lowlander that I've found doesn't mind the occasional drop into the high 50's...but long term it's still not good.
The trick with lowlanders is the really need hot days to thrive, with a few exceptions (like Bical), they don't mind suffering a few nights below typical lowland temp ranges.
If you're in danger of 40's though, get those suckers inside!