Integration Services :: Schema Separation - Accessing Multiple Databases

We have a system that uses 3 databases, one for Membership db standard MS membership only the application has access to that data, one with User Data which we would like to make multi-tenant using Schema-Separation, and a third read-only reference db which is Common Market data for all users.we anticipate Tenant numbers in the thousands.Current we have multiple queries which create joins between the Main db and the Reference database using something like

Selec S.*, M.ScheduleDate, M.substation from Sites S left outer join Market.dbo.MarketUnit M where S.MarketUnitID = M.MarketUnitID

i'm planning to have a new schema for each Tenant on the Main Database, so I would create a Schema T1 for the first customer, a user T1User with access to T1 schema.  and grant T1User access to Market.dbo. My First question is are there any concerns about the above T1User setup? My second question is, are there any tools which would automate the setup of the multi-tenant with schema separation, or should I just script the whole Main Database schema creation and replace schema name globally and then execute the script?

My Third question, how about upgrade and updates... currently using VS to compare dev/qa/prod database to identify changed which need to be promoted, and pushing updates...  this could be a big pain to promote code to thousands of Schemas.  grantedwe will likely keep the overall number of schemas spread over different SQL servers.