I cannot have any opinion about the current situation of Alan Webb, because I don't know the reality and I don't want to discuss the job of a coach that I don't know. When a top athlete runs not very well, we must know if the reason is because his training is poor (for example, the case of Shaheen at the moment), because coming from an injury, or is wrong (for example, using too more speed and little endurance, or viceversa). So, for the same effect, we can have different reasons.
But I can offer my opinion about what happened last year, as general principle, not specific for the situation of Allan Webb.
I think that Webb has to much pressure in US, since a lot of people not knowing the reality of athletics in the world speak about winning medal, like it was very easy.
Webb always showed a lot of talent, and a top aggressivity in his best competitions. Every time he won some race, he was very aggressive DURING the competition, maintaining a very fast pace during the last 2 laps.
Before Osaka, his shape was the best ever. But one thing is to run one mile in 3'46"91 alone, one thing is to win a TACTIC competition against Lagat and other athletes having the ability to change in very short time their speed.
Under this point of view, my opinion is that the 800m of Heusden under 1'44" was a result PENALIZING Allan, because after that race he supposed to be fast in the final.
Instead, running 1'43" with a first lap under 50", overtaking Reed in the last 30m because you have more endurance (so, you are able to control the decrease of speed, not to increase it), doesn't mean you can have the kick for changing from a SLOW pace.
If Webb wanted to use his attitude, he had to push very hard after 800m. This is the winning tactic for the most part of winners in 1500m in the history, not having a strong kick.
Some name ? Herb Elliot in OG in Rome '60 (world record with last 700m alone, in 3'35"6), Kip Keino in Mexico '68 (PB with 3'34"9 destroying Ryun in the last 2 laps), Peter Rono in Seoul '88, the victories of Morceli, the races of Aouita and El Guerrouj. Only athletes NOT VERY FAST in 800m, but very strong as muscular strength (for example, Fermin Cacho winning OG '92), could wait for the last 50m, having in the kick their best option.
About your second question, let me answer another time. I can suggest something when I understand HOW are your seasons, at the moment your activity is too much different from what we do normally with young runners in other Countries. In Kenya, for example, now I'm growing a young runner of 800m, born in 1990 REALLY (the most part of juniores are young like Passport, but are 2-4 years older), called Job Kinyor, that last year was n. 5 in decathlon in Kenyan championships for secondary schools. This guy NEVER went for real training, and in November was not able running 5 k under 19'. Now, already he ran 1'47"46 in Nairobi, is able to run 5k in 15'40" (nothing, but for a talented sprinter is ok), and to jump 1,80 with a style of 100 years ago, without matresses, in front.
We worked for increasing his qualities, and this type of phylosophy must continue for the next 3 years, if we want a goal of 1'43".
But, with your calendar (and I think that competitions for you are a must), is very difficult to have long periods of building up.
About the last question, 50% is talent (without this, no possibilities), 25% a good program, 25% continuity having full focus in your activity. Under this point of view,European and American athletes are very much better than African : if for white athletes to have great talent is an exception, for African to have professionalism and continuity is the exception. When you are able to combine BOTH the situations, you have the PHENOMEN (Gebrselassie, Bekele, Shaheen, Kipketer, Kiptanui, Tergat), that normally we cannot find among white people in those events.