I haven't read these yet (that's why I want to produce them after all!), so I'm working with what information I've been able to glean in summaries online. So my info may be incomplete, but high level, here's what I know:
The Big Town is a one continuous arc, but made up of five stories that could be read individually too. It's kind of like a serialized novel, but each part has its own individual storyline, so that each can be enjoyed on its own. The best parallel I can think of would be like a season of a modern TV show, where each episode is its own story but all together they form a singular larger narrative arc.
Same, presumably, with Lose With A Smile. That one follows the same epistolary format of the Jack Keefe stories and is tonally very similar, but follows a completely different cast of characters and is much, much shorter.
The Fred Gross Stories are objectively novel length altogether (I haven't tallied all of them up yet but they all appear to be roughly the same length so the final word count should be around 55k) but the connections between those are more tenuous than the connections between his other sets of connected stories. They all center on the same main character, but the stories are much less narratively linked, especially the last three.
He does have a set of travelogues that I believe would need to be produced as their own omnibus no matter what since they aren't fiction and clearly wouldn't belong in "short fiction". So if none of those collections of short stories sound like separate productions, maybe I could tackle the travelogues? If so, my question then is if we should just call it "Travelogues"? The first one, "My Four Weeks in France" details Lardner's time as a war correspondent in WW1, so "Travelogues", while technically accurate, doesn't exactly capture the mood of that story.