Yesterday I spent a few hours trying to get my german keyboard to let me use my umlauts (and to let me type without having to hunt down the right keys), but without much luck.
I got xkb installed after following this FaQ answer:
and this info:
(you can find the second under /etc/default/hurd-console ).
But I didn't get it to work.
What I did in short:
First I got the needed apt-sources:
Then I installed the xkb console:
apt install console-driver-xkb
And set it in the file /etc/default/hurd-console
Sadly it didn't work, but maybe this posts will give You the needed headstart for success (I'd be glad to see a guide from you!).
Some additional info: