Migrating from on premise Exchange to Office 365

We plan on migrating 70 users from on premise Exchange to Office 365.  The on premise will stay on the domain for a few weeks after the migration.  Below are the steps in general I plan to do.  I have a few questions.  

Is there a way to automate the removing of the old profile and adding the new one that will point to Office 365?  I'm trying to void logging into each desktop if possible.

Is there anything else I need to do to make sure Outlook doesn't try to connect to the old Exchange server?  It has to stay online for while after the migration...

Start the migration in roll ups from On Premise to Office 365 (while that's running start the below steps)
Schedule the last roll up to be done Sat evening
Then change public DNS to point to Office 365.  Then change the public autodiscover records and private autodiscover records to point to Office 365 for their domain.  
Log into each desktop, delete old profile, add a new one with a different name.  (see about a method that will automate this)
Configure profile to access Office 365 account (assuming there isn't an automated way)
Set Outlook instances that support selective offline cache to only sync back 3 months.  We can later change if desired.