Hello,
Just to make sure I understand, you essentially have access to:
- Page Name
- Page URL
- Login Status (use is logged in or not on every page/action)
But you don't have a "login" action (the actual "successful login" action)
Correct?
And basically you want to use sequential segments to determine the "action".
I have both "login actions" and "login status" and I tested this segment on our site, and got close values:

Basically, I am using a HIT based segment to try and get the first "yes" login status, following a sequential "no" then "yes".
Note that the container is set to VISIT and "Only Before Sequence"
HIT
VISIT Container (ONLY Before Sequence) [
Logged In Status equals no
THEN After 1 Hit
Logged In Status equals yes
]
AND
Logged In Status equals yes
I paired this segment with the Occurrences metric.
This will get you "Login" actions... but @robertblakeley is right, what is your definition of "Unique Logins"?