I heard that the latest Plazmic beta has options to add more than one web link on the home page.

Wonder whether this (these?) apps will still be necessary once themes start rolling out with multiple linking apps.

Probably, as tweaking settings on these shortcuts is possible on the device and end users won't be stuck with the option of (1) asking the theme developer to make specific versions just for them or (2) learning Plazmic and getting .thm files from developers.