ECA from 2 different agencies WES and IQAS

I am planning to get my ECA done again with a different company IQAS.
WES did not recognize my Post Graduate Diploma.
But I wanted to submit my Express Entry Application. Can I submit the application with what I have now and add the IQAS report later?

You should be able to submit the new report later. I have not tried it though.

For my Bachelor’s degree can I use what I have from WES and use IQAS for my PG Diploma once I get my assessment completed.

As in submit 2 different assessments from 2 different agencies for 2 different creadentials.

That should not be a problem as long as both are assessed by an authorized agency.