sure, lots of people have posted about multiple plantings. Dave Wilson Nursery in California is a proponent of it and has lots of info on YouTube. between those videos and searching this site you should be good to go. Backyard Orchard Culture I think is the title of the process. A lot of it is common sense. About your question, planting the least vigorous tree towards the sun will give it the best chance to thrive with the competition. Since yours is in the same pot just turn it around until the right orientation is found. With that said, DWN's plan usually involves some distance between trees. I think it was around 2 feet if I remember correctly. If your trees are a foot or less then that might be a problem.

Take a look on youtube and see what you think. There are people that think it's great and many that think it won't work. It seems to work in California but many people on this site say it will be difficult anywhere else.

Since you mention grafting, I would think that would be a far superior path than this specific pot you have in mind. Take some nice rootstock and over a few years graft a bunch of different varieties and enjoy! my $.02 so take it or leave it :)

i've looked at Dave Wilson's videos and they don't have a video for Triple Play plantings. Wilson's videos cover dense plantings and multi-grafted trees.

I'm concerned about how to plant the triple play because I just bought one. I have no idea how to plant it. Triple Play has three trunks grafted onto rootstock, and planted in one container. How will these trees grow? Apple trees have big trunks and branching. How do you plant these?