[Taqwus]

Simplify the problem and choose Deeply Religious -- a Nature Shrine acts as a VIP+CCF for the entire system (affecting only your own colonised worlds, that is -- not uncolonised ones.).

That's one VERY nice facility in terms of saving facility slots, construction time, and research.

As for stacking, urban pacs don't stack. I'm not so sure about VIPs 'tho...