>>24431265
I'd recommend 'Norrøn syntax' by Nygaard and 'Norrøn grammatikk i hovuddrag' by Haugen to people getting into learning to read ON, and those are specifically in Norwegian. For German, 'Runenkunde' by Düwel, but that's specifically for runology, of course.

Also on this:
>medieval Scandinavia in general
In Scandinavian context, the medieval period starts only AFTER the Viking age (they are starkly separated and the latter not considered to be a subset of the former at all), so that's something to bear in mind when seeking material on the matter in Scandinavian languages.

>>24432558
Fritzner's dictionary is the thinking man's dictionary, but requires knowing Danish to use in full. I believe The University of Copenhagen is actively working on translating it, and that many entries in their online version are now available in English. Otherwise, you have the slightly outdated Cleasby-Vigfússon, which has basically been 'the standard' dictionary in the field every since its conception.

>>24433082
No idea, but it's the best attested ancient Germanic by faaaaar, thanks to the hyperproductive authors of the classical period, so there's certainly plenty to read.

>>24433120
No.