For the Notification recipents, under sender name, is there an option to allow an email address rather than a name (first and last)?

Also, for the Notification recipents, under sender name, is there an option to allow an email address rather than a name (first and last)

As far as I understand, you would like to set user's email instead of a name here:

Correct? Sender Name can be only mapped to a text field. You can try adding a text field (hidden) and copy user's email there through condition. Then, additional field should be possible to map with Sender Name. 

Related guide: 

How-to-Insert-Text-or-Calculation-into-a-Field-Using-Conditional-Logic

Perfect, thank you!