X-Life mysteries

I have been practising  using x-Life airport editor using Edinburgh airport to work on and while finding 90% of it is excellent and works well, I have come across a few areas that seem to be stopping my enjoyment of it, either because of my lack of knowledge or a program bug.

1. There doesn't seem to be anyway of designating which AI aircraft can use a particular runway therefore jets are using the runway set for  props only.

2.Aircraft landing on runway 30 touchdown almost at the far end and obviously crashing. Landing on the opposite runway 12 is fine.

3.When an aircraft is landing or taking off all taxiway hold points become active for both runways thus stopping all taxiing aircraft all over the airport even though they are not anywhere near the active runway.

4. The biggest mystery of all is the piggyback takeoff and landing where two aircraft takeoff or land joined together. (See attached image)

I would be very interested to know if anybody else has experienced any of these.