Sql-server – How to find out that a publication has “replicated schema changes” enabled

I'm going to outline a T-SQL way that uses most of what you already have.

1. Create a table to hold your publication information (for the solution that I have written, it's just the name of the publication and an identity column)
2. Create a table to hold your subscriber information (in mine, I have name of subscriber, subscriber database, identity column, and a column that references back to the publication)
3. When you want to create a new subscription, you put a new row in the subscriber table with the relevant information
4. In your "add subscription" script, do a left join between your table and syssubscriptions to find out what subscriptions are in your table but don't yet exist. Run a cursor over that info and for each subscription that doesn't exist, create it.
5. After you're done adding all of the subscriptions, call sp_startpublication_snapshot for each publication that has uninitialized subscribers.
6. Fin (aka "you're done").

Yes, you can use the system stored procedure sp_addscriptexec to run an ad-hoc script on all the subscribers.