You don't need to do all that work anymore. In a recent update to the SharePoint Online PowerShell module, there is a commandlet to do this for you.

It is Request-SPOPersonalSite. You can enqueue up to 200 OneDrive for Business sites at a time.

$emails = "[email protected],[email protected]"
Request-SPOPersonalSite -UserEmails $emails

If you are going to do batches of 200 at a time, it is recommended to use the -NoWait switch.

Request-SPOPersonalSite -UserEmails $emails -NoWait

https://technet.microsoft.com/en-us/library/dn792367.aspx

You don't need to do all that work anymore. In a recent update to the SharePoint Online Management Shell, there is a commandlet to do this for you with much less effort.

It is Request-SPOPersonalSite. You can enqueue up to 200 OneDrive for Business sites at a time.

$emails = "[email protected],[email protected]"
Request-SPOPersonalSite -UserEmails $emails

If you are going to do batches of 200 at a time, it is recommended to use the -NoWait switch.

Request-SPOPersonalSite -UserEmails $emails -NoWait

https://technet.microsoft.com/en-us/library/dn792367.aspx