There are a few things you can do to get him through the 3-2 nap transition:
1. drop the CN cold turkey and push him as far as you can (I did this with DD, but she can handle OT fairly well - textbook/angel baby

). If your LO is awful with OT, do not use this method.
2. Cap AM and PM nap at 2 hours and allow a capped CN with a later BT to avoid an UT baby at bedtime (UT or OT can give you an EW). UT can also cause awesome crib parties at 2 or 3 am for an hour or more

The BT will go back to a more normal time once LO is ready to drop the CN for good.
3. if LO does well with it, use an early BT with no CN - you just run the risk of an EW

Given what I can see from your LO's temperament, I would use #2

And yes, it is okay if he goes down after 2.25 hrs as he adjusts to the longer A times... I would give him 5 days to get used to the 2.25, then push to 2.5 hrs.
I would also make sure that he had at least an hour of A time after solids before going to bed... a full tummy working on digesting food can cause wake ups.