Another Tom Bihn fan here.

For your one-night purpose, and given your list, agreed that the Western Flyer is more appropriate than the Pilot if shoes are involved. You might also consider the Aeronaut (comes in two sizes, 30 and 45, 30 will do for an overnight and can handle a pair of shoes).

Now, of course, in your quest for One-Bag travelhood, if you start doing *several* nights, and you want only one bag, then you might want to choose something on the larger side (from small to large of your candidates):
Pilot (13 l.) < Western Flyer (26 l.) < Aeronaut 30 < Tristar (33) < Aeronaut 45

All the above bags will fit under the seat in front of you, and in *most* overhead bins. The first three (Pilot, WF, and Aeronaut 30) are also most likely to also fit in even the tiniest of RJ overhead bins.

So...I'd recommend either the WF or the Aeronaut 30.