Are disabling and enabling foreign key constraints supported in SQL Server? Or is my only option to drop and then re-create
You should actually be able to disable foreign key constraints the same way you temporarily disable other constraints:
Alter table MyTable nocheck constraint FK_ForeignKeyConstraintName
Just make sure you're disabling the constraint on the first table listed in the constraint name. For example, if my foreign key constraint was FK_LocationsEmployeesLocationIdEmployeeId, I would want to use the following:
Alter table Locations nocheck constraint FK_LocationsEmployeesLocationIdEmployeeId
even though violating this constraint will produce an error that doesn't necessarily state that table as the source of the conflict.