Not sure of impact of "C + 2 data", but it sounds like what you'll probably want to do is set up continuous transactional replication publications on each...
Don't know about pre-7 versions, but SQL Server 7 / 2K both support updates via transactional replication. I.e. they either send actual SQL UPDATE statements or call custom stored...
I know you can skip selected errors in SQL 2K, i.e. "On the -SkipErrors property you can put 20598.", but is there anything similar I can do for SQL 7?...