If you're trying to get the first nap longer you could try just lengthening that first A time. The move to a 4 hour EASY doesn't happen in one jump, so moving one A at a time by say 10 mins and then hold that for at least three days to let your LO adjust before lengthening again if needed is a way to help move to a longer EASY pattern while still following your LOs cues.
You will find that he will still likely be cranky at around the same time but once he adjusts to the new A time this should reduce. LOs get used to the time of their sleep and it can take a little getting used to to move it.
You may find the second A time could do with a bit of lengthening too, before the nap gets too short. Later naps I the day look better, but this might be because that same A time is ok after two shorter naps earlier in the day. You might need to lengthen later A times too but see what happens with the first one first.
What do you think?