VBS Merge Request - Main Branch

Summary:

Lets take up a scenario where MAIN branch is used only for production deployment.

The branches hcm_dor_working_branch and hcm_employment_working branch are created off MAIN to have respective changes for respesctive pages.

Now, hcm_dor_working_branch is to be merged to main (using merge request) and post merge the branch is deleted.

The buid runs and the changes are pushed.

Now,
1) do we need to pull the changes from MAIN to hcm_employment_working_branch considering this branch was created before hcm_dor_working_branch was pushed to main

2) if we dont do the above, is there a risk of wiping off the changes earlier merged to main using hcm_dor_working_branch?