These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Les Yay: Potentially between the next door neighbor of the Isaacses (who turns out to be the phone operator, Elodie) and Abby, who certainly drinks it in as she watches her change through the window in episode one.
In-verse, as Abby finds out some people will have phone sex even with someone else potentially listening in.
The show rather graphically shows the effect of Frank Winter having accidentally stepped on some old shrapnel.
They also show the effects of Chlorine gas on Frank's squadmates back at his trench.
They Wasted a Perfectly Good Plot: Sid could have become a double agent reporting back to G-2 about why Frank had been away for a year in the late 1930s, seeing as he knew Frank had betrayed him to the Army to get his group back together.
One possible reason for this is because the Manhattan Project really did have a spy in their midst, Klaus Fuchs. If they have plans for his story later in the series Sid spying on Frank might be irrelevant or unwieldy story-wise.
UST: Between Dunlavey and Frank Winters's daughter.