Answer to Q1:

Merged replication is somewhat different to what you presume. The Merged replication allows to update the Primary server from the secondary when any change occurs in it. It has nothing to do with merging databases.

You can implement your plan, using DTS in SQL 2000 or SQL Server Integration Service from SQL 2005 onwards. Note that you can schedule the transfer as easily as in a replication.

Hint: You can have triggers, which keep track of inserted, updated or deleted data in a table for the duration post execution of the job upto the time of execution. In the job, you can just insert the inserted, update the updated, and delete the deleted. You can also have a separate table to log the changes happened and the changes applied.

Hope this helps.