Along a new user registration process, I would have liked to email them, get them to click on a unique link, so that I verify that the email address is theirs, and continue the registration process.
Is that doable on bubble? If yes, how? If not - does anyone have a workaround?
Yes it is possible. The how portion I believe has been covered in various threads. I would suggest trying to search the forum for the answer…seek and ye shall find. 
This may help, it’s not exactly what you want but points you in the right direction, which does send a link but also shows how to setup a verification code.
And another option to check when the user signs up to see if the email is valid
