Maybe because she didn't take the catnap, there was more drive to sleep at night, which is what makes me think she might be ready for the 3-2 nap transition.
But in any case, yes, you could ideally stop shh/patting when they start settling down and I would probably continue shushing and stop patting for a little bit longer and then stop altogether and wait a little. If she starts to cry again, you could start shushing again and then stop again once she's settling down... you know she's going down from the really hard cry (the i need you now cry) to the mantra cry. I used to leave the room altogether as having me in the room would wind mine up even more. Also, I found when sending DH in, she would settle much sooner than when I would try and do it... probably because I would get all anxious about her not going back to sleep and he wouldn't and babies are good at picking up on our vibes!
When you do start adding more A to get rid of the catnap, I would suggest 15mins every 3-4 days as you don't want her getting overtired. I found it was much better to do an earlier bedtime than the catnap towards the end of the transition, so for example, if her 2nd nap ends around 3pm, I would do a bedtime of 5.30pm and she would usually sleep until her usual wake up time in the morning. But that all depends on whether your baby is good at tacking on. If you feed like that bedtime would be much too early, you could try a super short catnap (so say 30, even 20mins) just to tie her over to bedtime.
Please let me know how you get on over the next couple of days.