1- How solid is the evidence that there really is any difference between different training types in the training speed for the primary skill?
5- Will a player train equally fast for, say, IS at C and PF respectively, considering that IS is apparently relatively more important at the C position than at PF?
6- I'd appreciate a link to a good post that describes the exact relation between age and training speed.
Just saying, I think it's good news to see a guy who only played 40 minutes pop. It shows that the training curve might not be as steep as some people think.
Try to give 1 player of 18 years old 24 weekly minutes 4 weeks in a row with rebounding training, see what will be the effect. It's probably the only way to check it.