What's your question? Ask

From what I've read, this tree shows off best as a single trunk. If it were mine, I would take the two rouges out/off. This pruning will probably make your plant look less full, but with time and age, it will fill out and look as it should.

This conifer is best adapted to the areas west of the Cascades where summers are mild and winters are wet. It should be protected from drying southwest winds. It does best where the soil is acidic. To ensure best growth give this plant full sun.

Sorry, but I don't know what a cedar pine is. Cedar trees can be planted in a
row to act as both a privacy and wind break. Pine trees can also be planted the same. There are many evergreen shrubs, such as holly, azalea, juniper, yew, cypress, arborvitae, and many more that make a nice hedge.

Yes, you can. This article will help you with the soil mix: https://www.gardeningknowhow.com/special/containers/proper-soil-mix-for-evergreen-container-plants-and-trees.htm

If the tree is only half-dead, and you can determine the cause of death, and take steps to stop the dying, then the tree might live to a ripe old age. So what happened to the tree -- was it injured by lightning, or a lawn mower, etc? If not damage, look at the tree trunk -- are there slimy or weeping or peeling spots? Then look at the leaves -- are they brown, yellow, white? Are there spots? What do the spots look like, and where are they? Are there bugs on the branches, or on the leaves? These are just a few of the things to look for. If you want to save the tree, you should probably enlist the help of a professional, an arborist, or someone in the Master Gardener program which you can access through the nearest botanical garden. In addition, here are a couple of articles that might help you: https://www.gardeningknowhow.com/ornamental/trees/cedar/growing-cedar-trees.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/repairing-tree-bark-damage.htm
As for growing a vine, there are many you can choose from. Many of these would work for you -- make sure any vine you choose is hardy in your area: https://www.gardeningknowhow.com/ornamental/vines/ovgen/growing-plant-cover-fence.htm

The most critical measurement would be the depth of the container. 16" seems very narrow for a 5-6' tree, but if that's what is demanded by your space requirements, you need a container at least 2' deep, I would guess. Here are a couple of articles that will give you some tips: https://www.gardeningknowhow.com/ornamental/trees/tgen/growing-trees-in-containers.htm
https://www.gardeningknowhow.com/special/containers/how-to-grow-container-trees.htm