I use a 6 gallon glass carboy but so many people use the 6-7 gallon food grade plastic bucket that I have no doubt those are fine. I usually let it sit about 3 weeks in the primary fermentor, then about 2 weeks in the secondary with some pectic enzyme to clear it up, but that's strictly optional.
As for yeast, most dry yeast packages are the correct size to add one pack for 5 gallons. Some of the wine yeasts, like Lalvin EC-1118 are smaller packs so you would add two. If in doubt, ask your LHBS.
If you want sweet, carbonated cider, follow the sticky on pasteurizing to a T, you can't go wrong.