It's totally up to you if you try extending in the crib and then AP or give up and get on with the day. I don't think you will have any long term problems if you AP, the 'risk' is that this becomes a prop that is later worked on to get the full nap in the crib, the 'benefit' of APing the extension is your LO is well slept and happy. Only you can decide based on your family commitments and how you are feeling at the time. If you start feeling trapped at any point I think it's better to get on with the day.
As for the second a time, hard to say, my DS would go almost a full A time on a short nap as though he didn't realize he'd only had a short nap. Observing your LO will help you make the decision, not necessarily observing sleepy signs which can be misleading, but noting how long the first nap was and how well he does with the following A time and, over time, whether he does better with a reduced A time or a full one. No problem starting with the 1hr 55 and seeing how it goes for a while.