Surface Pros already have a wireless adapter built into them, so a USB network adapter is not necessary.

Not necessarily - this depends on your organization's Wi-Fi policy. Many organizations have more locked-down wireless policies than wired policies, because wireless is newer and therefore easier to lock down from the get-go as we start to care about security more as we implement new systems. Of the last four companies I've been with (including two fortune 100s), wireless imaging was not even an option worth considering or that would be approved.

To OP, I would always recommend wired connections for imaging, if only for multicast (can you do multicast Wi-Fi imaging?). If that means you need to buy USB-to-Ethernet adapters for each concurrent connection, so be it. If you're doing it in huge quantities, it seems worth it. Otherwise, do 5 at a time, 10 at a time, or whatever you determine is worth it?

You seem level-headed. What you think is best is probably fine. Unless you are an org of 300k+, don't worry about what's most optimal.