Is there any requirements on the type of ticket to be eligible for the 144-hour visa free transit?

There does not need to be an interline agreement between the airlines. You just need confirmed tickets. Standby is not allowed. Separate tickets and different carriers are both fine.

You do not need any interlink ticket or similar. You have to fulfill just two criteria:

- Your ticket should not be a stand by ticket, but a confirmed one, with fixed dates and you are allowed to travel on separate tickets and on unrelated airlines. You can have one ticket for your Vancouver to Beijing and another for your Beijing to Phuket segment. It can be on different airlines also. Just to add, you can even use different airports in Beijing.
- You have to have an eligible journey (itinerary). Your itinerary as long as you have mentioned your all stops, is definitely an eligible itinerary for 144 hour visa free transit in wider Beijing area.