Ah shame, these things sometimes happen & you did the right thing offering her an earlier bedtime.
I still think the short naps are leading to her becoming OT hun. Its so, so similar to what my DS did when I cut his nap back. I know on the first night she slept a long night, but after 2-3 days of shorter naps, she is suddenly taking longer to fall asleep at bedtime & the NW are increasing, and she fell asleep early for her nap today, despite having had a long night which should have left her feeling refreshed. IMHO these are all indicators that she may struggle with a short nap on a long term basis. At the end of the day you can't really get a feel for whether it is working or not after just a couple of days, you would really need to try it for a good couple of weeks & see how she does to make a decision for sure.
WRT the longer nap, all I can say is you won't know if it works or not without trying it. And whats the worst that can happen if you do? OK she may have a long NW, but then you will categorically know that it is not the way to go, and you will also know what you need i.e. shorter nap. I only keep harping on about this b/c I too spent many many months capping my son's nap short, b/c he EW with long nap & as a result of the short nap he had crying NW & restless nights & looked tired & still EW. Now he is napping longer it has all stopped. His night is shorter, no getting away from that, but he is well rested & far far happier. I can tell you're not keen though, so for now I shall keep quiet on this subject!
Hope she has a decent night.x