My Bot is using meta_p for getting a list of all available wiki. Currently many of my scripts are failing because gomwiki and lrcwiki are listed at meta_p.wiki but not available on labs (see T103794) . So in future please add those new wikis to meta_p.wiki after replication and host asliases are created. Alternativly a new boolean column which indicates if db access is available or not.
The process that updates the metadata uses the global mediawiki-config repo as its source of authority, and I don't believe that there is a way of knowing in advance whether its contents have propagated. Because what is or isn't redacted is independently managed, I think it would be wisest to have any code that enumerates meta_p.wiki have guards against projects being there but not replicated.
That said, I'll look into adding a check after my return from Wikimania to avoid having early or unnecessary entries.
After inspection, it's not reasonable to make the insertion of entries into meta_p.wiki depend on factors outside the actual site configuration.
I think that the proper solution is to have any code that enumerates databases actually guard against a db being listed but not, in fact, available by checking the error when attempting to connect.