CF fast (or CFast) definitely NOT compatible.
It will DESTROY the pins in your OT if you try to force one of those in there.
As for brands, and being in the photography trade for 27 years, I started out with Sandisk but moved to Lexar about 10 years ago after the release of some independent industry data on read/write cycles before failure. But that was a while ago, things change and most photographers use both from what I see. I still used old Sandisk cards in a pinch and the only failure I ever had was due to the camera, not the card.
The ‘best practice’ is always double backups, format the card (overwriting and filling CF cards is death), and take advantage of downloading that free recovery software that comes with a new card.
The data rate limiting factor and largely the card dependability factor rests on the OT (or camera) drivers, hardware etc. Also, it gets weird, a device may work perfectly with CF cards up to 16GB, then fail or struggle with 32GB cards, then work fine again with 64GB, and not work at all with 128.
So best stick with what Elektron advice on card capacity.
Anyway, my Nikon’s now use XQD cards (PCI based) so I’ve got a stack of CF cards waiting for an OT 