The best way we found to mount things to the thin 1/4-inch walls is put up a large 3/4-inch or 1-inch solid board first to spread out the weight of the item you are hanging and connect your hanging adapters to this. You can paint the back board to fit your dicor.
We have used these type of metal anchors in the four corners of the wood pieces if we were unable to directly screw into to a solid small wall stud.
photos from google images
I prefer the MOLLY BOLTS over the SPRING WING TOGGLE BOLTS as the when you remove the screw in the MOLLY BOLT it will stay in place on the wall. If you remove the screw in the SPRING WING TOGGLE BOLT the n the back part will drop down behind the wall. The SPRING WING TOGGLE BOLTS with large washers behind the mounting screws would probably hold up more weight than the MOLLY BOLTS will.
By spreading out the weight using the full size board first really allows you to safely hang up something that is very heavy. The 15-20lb TV's stay in place with ease using these type mounts
If you buying the swinging pivot arms mounts try to locate one that allows you to remove the pivot part with ease so you can easily remove the TV from the wall for what-ever reason.
Another note along this line is in some model RV's the manf has already mounted thick solid walls where the TV mounts is to be installed in the bed room area. Might check that out on your schematics.