I don't know the answer to #14
It's a trick question, like asking "How high is up"?
The answer will depend upon many things, and is actually completely irrelevant. Closing speed will be a function of aircraft type, angle of bank that the lead has on in the turn, how much lower you are than the lead at the start of the joinup (obviously you're going to convert airspeed into altitude), aircraft equipment (speed brakes) and configuration, and pilot skill.
Let's say you actually crunch the numbers for the above. It's almost completely useless except as an initial starting point, because the very last thing in the world that you want to do, during a joinup, is go under the hood and start staring at the gauges. A joinup is a completely visual exercise, like catching a baseball. You want to have your eyes on the lead the entire time, to closely observe your rate of closure ie how fast is he getting bigger?
As I mentioned before, if you have too much energy during a rear-quarter joinup, just push the nose down, and go under the lead (and the rest of the formation already joined up on him) and join up on the outside of the turn of the lead, instead of the inside. A tad embarrassing, but not fatal. If you really have 'way too much energy during a rear-quarter joinup, it's your birthday. You know why? Push the nose down to safely go underneath him, then pull up and do a barrel roll around him, to join up on the inside of the turn, as originally intended. If that's not fun, I don't know what is! I think you can probably guess where my throttle is, during a joinup. Heck, if you have a 200 mph delta on the lead, feel free to do as many barrel rolls around him as is necessary until you have equivalent total energy.
As I said before, a joinup has really nothing to do with close formation. You can take off and land in close formation and be awesome at flying wing, and have no clue at how to do a joinup, if your runway is wide enough to permit formation takeoffs and landings.
But joinups are extraordinary fun. You start off with rear quarter joinups, then after a while you can progress to front quarter joinups, eventually from pretty much head-on. It's a hoot. What I use for a front quarter joinup is basically pulling up through the vertical to the inverted 45 above and slightly behind the lead, and then a barrelled 1/2 roll to upright into position behind him. The trick here is to convert your airspeed into altitude which means that the radius of your 1/2 cuban eight is very tight, with the slow airspeed. Timing is critical to doing this right. Again, all looking outside, not inside at the flight instruments.
The romper boys call this a high yo-yo:
http://www.combataircraft.com/en/Tactic ... eed-Yo-Yo/
If you have an experienced ex-military (fighter) pilot as lead, during an interesting joinup like this, he may not be able to humanly resist putting his lift vector on you, and then the fun really begins
I know many people here think that I'm not a very good (formation / aerobatic) pilot compared to them, so I would be interested in how they perform front-quarter (head-on) joinups.