I love, love, LOVE this idea and it would be super handy, but the results only apply to the network I'm physically standing in. If I remotely view some other surface and open the logistic networks there, that network should be what is searched (basically, whatever network applies to the thing I Alt + Z over).
When viewing my local network:
https://i.imgur.com/yfpeoqu.png

When remotely viewing a different network:
https://i.imgur.com/PLn7k25.png

How are you selecting those items remotely? Are you picking them from your inventory, or another inventory?

There's no way to get the position of the map editor, so I need to work around that limitation

Fixed in latest release, remote viewing and cross-surface searching is functional.

I am picking from placed entities in the world or from the inventory of placed entities. Interestingly, it looks like you are using the center of the viewscreen to determine logistic network at time of picking? I have a specific case on Fulgora (https://i.imgur.com/KNiB1H0.png) where I've got a "bridge" of sorts between two distant logistic networks (to reduce robot fatigue) and I have to make sure I am also roughly positioned over the logistic network of interest when I pick something inside it.

Good enough, I'd say!

Yeah, the event I'm hooking onto to do the search functionality only gives me the base prototype of the thing selected (item, roboport, assembler, etc) and not the actual entity that is selected. I can, however, poll the surface for logistics networks at the "position" of the player (in map view, the center of the screen) so that's how I search for logistics networks.

I might end up adding a check that, if no logistic network is found, and only one network exists on that surface (planet) then just use that one. Does that sound like a reasonable compromise? I might also look into a way to find the nearest logistic network based on the player's position.

Nearest network would probably work well. Nearest Roboport by definition, but I suppose mods could create non-roboport logistics networks?

Biggest part is done though, this would be polishing up the UX.

No, all logistic network extenders and other buildings are roboports in disguise. Either way my "search for network" function might get a bit computationally heavy. I'll see if I can come up with something that won't require a supercomputer.