3.) I've bought 680 with AZERTY (FR) keyboard and windows, but I'd
like to use typical QWERTY. Can I just use us keyboard mapping and
stickers on keys?
Yes, you can. But don't use US, use European. US layout has fewer keys:
http://snark.ptc.spbu.ru/~uwe/netbsd/jornada/keyboard.html
But please, can you test if "French" really works and matches what's
written on the keyboard?
I used mhzc(4) (a combo card with sm(4) for the ethernet). I
currently use an ne(4) clone.
ne0 at pcmcia0 function 0: <Dual Speed, 10/100 PC Card, 1.0, >
nsphyter0 at ne0 phy 4: DP83815 10/100 media interface, rev. 3
nsphyter0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
Getting a card that WinCE recognizes out of the box, or that at least
has WinCE drivers for it is a good idea. So I'd say - look for ne(4).