Domain Swapping

Hi All,

I have a site, mysite.com - which serves CANADA
then i have, usa.mysite.com - which serves USA

These sites have identical content**

recently we were able to get mysite.ca

Ideally, we want

mysite.ca to be for canada
mysite.com to be for USA

A few questions i have
1. Will simply setting up a permanent 301 on all usa.mysite.com -> mysite.com on Go Daddy DNS management suffice to transfer all link juice and redirect any links to our site? Because i am using a hosted ecomm solution and the domain will no longer exist, i will have to redirect to usa.mysite.com to an actual webserver to manage the 301s.

2. Its kind of weird because mysite.ca will be seen as a brand new site on google. .com ranks really well right now, so im sure canadian users will see this in the SERP still until google can pick up on the HREFLANG settings? We do have an IP detect installed that will check users location and inform them via popup that theyre on the wrong site. Which leads me to point below....

3. How can i properly setup HREFLANG tags to ensure that google knows .ca is for canada and .com is for usa. Or will google automatically do that for .ca ?
I dont want either domain to over power each other on SERP (Like .com showing up for canadian users) if possible.

If there is anything else you think i am missing that is majorly important please let me know. Of course i will be changing all my google and facebook ad urls to match accordingly.

You are in luck, most of this has been covered before! You will find most of what you need if you do a little research on "301 vs CNAME redirect" also "canonical and hreflang". Here's a good starting point.