Let's see what happens. She had 11,5h day and 1:45 nap so let's see when she wakes.
If she wakes after 10-10,5h, it will be MOTN so just treat as NW and try to make her to go back to sleep. If she does 11,5+ I would stretch her morning A to 5,5h and afternoon one to 4,5h at least. It means that you are working on 12h night, 10h of A and 2h nap which is 14h of sleep for 24h. You cannot count on more according to what she was doing before.
I know that this might be difficult but I would firstly try to have a working routine even 5-5 with 11-12h nights and than try to switch - if you still want to work on one nap.
Another option I would consider is accepting that she is not yet ready for a full one nap routine and maybe offer a morning catnap of 5-15min and later midday nap so she is not so OT. Kelly will probably pop in soon but she told me that was her routine in transition period, and I am also probably going to try that with my DS.
So something like this:
5am wakeup
7/7:30 nap for 15min
11:30-1/1:30pm nap (or any other time - you have to get a decent sleep here)
6pm BT the latest