The devblog on hacking covers most of the basics, and via personal experience and a quick refresher at the UniWiki Odyssey page I have this to say:
There are five different kinds of nodes: Empty, System Core, Data Cache, Defensive Subsystem and Utility Subsystem - with the defensive Subsystem and Utility Subsystem having a few flavors each. Data Caches are either Defensive or Utility Subsystem.
The damage is consistent per node, but different types of the same node are random within a specific set - i.e. the same node will always hit you for the same amount, but another node of the same type may be different.
Yes, but the number of released containers increases, without increasing the amount of available loot, meaning each individual container will have less in it. However if you fail too many times (currently 2) then the loot will be destroyed.
Additionally, the profession containers can be cargo scanned. If the loot isn't overly valuable, skip it. The ISK/hr may be better without wasting the time.
Extra extra additionally, Ali Arias wrote a detailed piece of the entire process over at themittani.com. It's a bit of a read, but it covers all of the salient points.
Once you've won the mini-game and the look has exploded into space you have about 10-15 seconds before the last of it disappears.
The individual containers are divided into types (currently Data, Materials, Parts, and Scraps) with their contents being determined according to their type. Scraps containers are effectively worthless, don't waste time on these and reliably collecting all the loot requires at least 2 characters doing it.