I am compiling another how-to and am trying to cover most all imaginable cases. If someone does not have an Ethernet connection but does rely on wireless only, they depend on side-loading the extensions for wireless from the dCore-repo. There is wireless-<KERNEL>-tinycore.sce and wireless.sce available which is good.
However, if the wlan-nic needs firmware then one is quite at loss. Would it be possible to include the (Ubuntu) packages linux-firmware as well as linux-firmware-nonfree (and similar for Debian) in the repo? One down-side I can think of is that these packages occasionally get updated so one would have to make sure they are sort of up to date.