If the US Navy received a handful of ex-German capital ships and a pair of Zeppelins, they would need to learn how to make ammo and spare parts, overhaul engines, etc. Ergo US Navy Yards adopted metric tools decades ahead of the rest of the USA.
Would the USN lead the American conversion to SI metric units?
Why would the USN want some used Battleships for anything for more than testing purposes? They would be non standard, and the
Colorado's and
South Dakota's on order are far better. The French and Italians are the ones who might consider taking ships into service, especially the Bayerns and the Battlecruisers, and maybe even the Konig's.
There's at least one timeline on this site where the recipients of the German ships needed to contract maintenance of the ships to a German shipyard preserving German ship building capability going forward into that timeline's WW2.
The thing is, I can't see the Germans being that co-operative. You might get technical drawings, and possibly some bits made, but I could imagine the French getting very jumpy if the saw that the Germans were using it as a opportunity to keep a skill base alive. Of course, if the Germans get to keep some of the older dreadnoughts, then it might not be such a concern, but on the other hand, apart from the French or Italians, who else would want old German ships. The Greeks might like one or two, if it is cheap enough, but then wouldn't it be simpler to approach the British government, and ask to buy, say HMS Erin, on the grounds that shells are likely be easier to obtain and Vickers/Armstrong Whitworth more likely to provide support than the Germans.
I think the majority of the HSF will be scrapped, but some might survive IF
a) A major war breaks out before 1920
b) The French or Italians keep one or two of the more modern ships (And they would have to survive ITTL Washington Naval treaty.)
c) Some other country buys one. Poland? Greece? Yugoslavia? Spain? Finland? Sweden? And of course, it needs to have something over available British ships, which the British government may have been in the mood to sell.