Yes PLA can afford it. They can even afford to have a third 6th gen design if they wanted.I don't think PLAAF can afford two different classes of 6th gen aircraft's. And so far we have not seen J-50 showing features for carrier uses. We will have to wait and see.
You are rehashing an old debate about whether J-SX is for carrier use as well. Check the old pages, but to save you time, it's very, highly, likely to have a carrier version due to its smaller size and maneuverability compared to J-36/J-CX.
the j-50 will eventually replace the j-20 and j-35? or the j-36 will replace the j-35?
Current 5th gen fighters--J-20 and J-35--are serving alongside 4th gen and even 3rd gen aircraft.
Future 6th gen will serve alongside 5th gen and also 4th gen aircraft.
Ultimately the 5th gen fighters are replacing 3rd gen fighters and likewise 6th gen fighters will replace 4th gen fighters.
Everyone has a high-low mix in their force structure because no one has the luxury of forming only high tiers force structure.