I looked at those notes and tried replacing the DDLHDB.TPL file, but the issue was same. I have ignored these error's in task files for now, migration is resumed as of now, not sure what will be the impact. I have listed the tables which were having issues, may be useful to cross check if migration is successful.
I did not follow 1792686 - Error during system copy on HDB after update as it says "Take note that you cannot complete the already started copy because the export tasks must be regenerated" . My migration import process was already started hence ignored
Thanks a lot for your quick response and idea's.
Hope it goes well 