In trade status , but no afterpay or ping as a payment option

There could be a couple of reasons this happens:

People who have recently had "in-trade" switched on but their items haven't caught up. 

There are also a couple of well known large sellers who have a private arrangement with Trade Me that allow them to not have it.

Otherwise you can Community Watch that members items and get Trade Me to take a look. 

If it's a seller you want to purchase from, ask them to add Ping / Afterpay, assuming that's the method you want to use to pay.