Data repication to SQL from Proprietary DB

Hi

I am looking to establish tables replication from proprietary DB to SQL DB near real time. I am not sure what method I cound get it.  I fould this artical may help me to do table sync from propritery DB to SQl Server. But I noted on propritery DB tables
do not have any "Id" column to identify raws uniquely.
Q1. Can we create in Sql Server side "sequence" which create unique id when insert a record.
CREATE SEQUENCE [<schema_name>.] <sequence_name>
Then create a trigger on table when add a records then add new sequence no to relevent raw. (We do not able to change the application codes)

Q2.Any other way to do replicate data(change data uptodate) on this scenario 

link:

https://www.mssqltips.com/sqlservertip/1704/using-merge-in-sql-server-to-insert-update-and-delete-at-the-same-time/

many Thanks