Hello Robert,
Please go through the below ans to the questions.
1. As per my understanding You cannot skip a column for replication but you can defiantly mask the table columns in tcode iuuc_repl_content
2. whenever you make any changes to the table in source system you will have to replicate the table from SLT system for below 2 reasons;
--> once you update any structure for a table the triggers on the table created by slt system will be deactivated thus the replication will not be available for that table
--> HANA system will only understand the data coming via SLT system thus it will not be aware about the structural changes done to the table thus replication for that table has to be restarted.
to restart replication of the table
login to SLT system
load the MT id for tht replication
go to table overview
click on data provisioning
give table name
select stop replication
click ok
in similar way start the replication of the tables
this restart of replication will remove the logging table and the triggeres and recreate them as per new structure in case of any changes done.
Let me know if this helps or if you need more information on this
Regards,
Amar