[1] - Any time
[2] - Crappie will hold on condos all year long depending on food source, depth, water temp. Condos are most productive I think in summer and fall.
[3] - Depending on location, you can place condos and catch fish off of them the same day. Most of the time it takes a couple of weeks or more before they are really productive.
[4] - Most places are okay. Some are better than others. We generally place them close to drop offs or depth changes or on long flats. Just don't add a tree to the forrest.
[5] - We use 5 gallon buckets as the base. If you lower them using a rope, they should stand straight. Most of the time we just chunk them over and hope for the best though.