Hi.
First, I'm not sure I agree with your initial order of events. There seems little or no point doing the static stretches before your sport, since this is more likely to reduce coordination. It's better to do sports-specific dynamic stretches to get ready for your sport, rather than static stretches.
Also, you've done dynamic stretching, then your sport. It seems a little pointless to repeat the dynamic stretching, unless your sport makes you feel really tight.
So I will answer the questions, assuming that the following is your basic structure:
joint rotations- aerobic- dynamic- sports activity- static
1) The splits training (like isometrics) should be done before, or instead of your static stretches at the end.
2) If there is no sports, then do them in place of the sports activity.
3) I don't know what you mean by work hard on dynamic stuff. This is not ballistic, so there should be little in the way of effort. There should be no hard work involved. You dynamic work should always follow the same pattern. Swing in a light, controlled manner, gradually increasing the magnitude of the movement, until you see no further improvement. Hacking away for ages at your maximum is more likely to tighten you up than improve your dynamic flexibility.
4) It's the same as your normal pattern, but with the sports activity removed. As for cool down, I don't see this as necessary. Static stretches are in themselves a cool down. If you are relaxing into a stretch, your heart rate will not be exceptionally high, and you will only have a light sweat. There should be no strain or gnashing of teeth.
5) If you are naturally strong, and your training involves holding deep stances for a long time, you may not need additional strength training to get splits. That doesn't mean it isn't advisable, but it may not be necessary. If your stretching plateaus, work on increasing your strength using weights and/or bodyweight exercises. PNF does increase strength in the stretched position, but it is unlikely to increase strength as fast as weights. Weight training is a tool to assist you, not the holy grail.
Just mu thoughts.
Cheers
Tim...