What is the general practice for finishing a basement in a town home to code?

I plan to finish my unfinished basement and pull a permit for it. It is a townhouse with neighbours on both sides.

For the common concrete walls, which are walls adjacent to my neighbours' basement, does it need to be insulated? If not where can the I insulated portion start? My current common concrete wall is bare concrete after 2' from an exterior facing wall, which I believe is code for unfinished basements.

Secondly, I plan to use 2 xps rigid foam board plus batt for the exterior facing walls to get R22 (or even R30 if I use R20 batt). For the common concrete walls, could I caulk and seal the xps then use house wrap for the common walls just to prevent wood to concrete contact, or use a thinner xps to create continuity in the barrier? My preference would be to not use 2 for those wall because of limited spacing in some areas.