Just to play German head teacher: It's Bier, Kraut, Wurst, Wiener Schnitzel, U-Boot, das Boot and Gert Fröbe. We capitalize the nouns. The articles aren't capitalized, except at the beginning of a sentence or of a headleine (not within a headline).
The crossword puzzle convention is that umlauts are written as two leters, ae,oe and ue, and that ß (originally sz) is writtes as double s. It gives a crossword puzzle writer more freedom. In Scrabble, however, there are umlaut chips with high values (Ü, 5; Ä, 6; Ö, 8. X has 8, and Y and Q have 10) but no ß, which is also turned into double s.
As for Spanish, I don't know - but I learnt ll and the tilded n as distinct letters, so I would expect... ah, well, here's the
Wiki!