Question #1) It is always recommended that you prune after flowering is complete and before buds are set. Buds are set around the start of August in the south. The further north you are, the more additional time you have. I have personally used August 1st here in Texas. If some of the problem stems have no flowers or if you do not care about this year's flowers, go ahead and cut those stems now.

Question #2) I recently read in the American Rodhie Society Website that, if you cut the end of most any branch or twig that is not heavily shaded, you will start new buds below the cut end; the plant uses something referred to as adventitious (sp?) buds to regenerate.

Check the information on the website below,
Luis

Here is a link that might be useful: American Rhododendron Society Website

Azaleas have growth buds all along their stems just under the bark surface. New growth will originate close to any cut you make.

They do set their buds in late summer for the following springs flowers; if you are going to prune, do it immediately after, or during, flowering so as not to lose a years worth of buds.