I would suggest to try something like a GSA SER friendly mail server for GSA Search engine Ranker:
http://selos.link
In this case, you use the domain of your choice with multiple alias mail accounts. So, you can change the email accounts very often & the catch-all email account will get all the mails who are sent to any aliases. plus, you can use several domains.
From my own experience, i have been unable to create bulk yahoo account with softwares & with hotmail the emails software generators are pricey. Plus, when you end up with mail accounts like X34jdsAThotmail com
That looks too spammy to me. It is better to have your own domain & human aliases like john.doe at yourdomain com