I can't answer your questions, but 4:08 is certainly a very good time.
A junior in Arizona - Bernie Montoya - also ran a slightly slower 4:08.8 at Chandler on Saturday but hasn't gotten much attention. And a kid who had come down from Idaho for the race, Eric Harris, ran 4:09.
It's hard to know what these very fast times bode for the rest of the season without really knowing the inside scoop on each individual athlete - have they peaked way too soon, or are they still in early training and will run even faster later on? I have no idea. Looking at other sub-4:10 high schoolers, it seems like many of them do it only once, others a couple of times. Few race at that level consistently in every race.
If those are Fahy's goals in the 3200, more power to him - wanting to hit those times and actually doing it are two different things, of course - there are so many variables, even stuff you can't control like weather, illness, how other guys are racing, etc etc. But he is clearly a very talented runner and it will be fun seeing how he does. What did he run at Arcadia last year, 8:55 or thereabouts? Only a couple of guys in the whole nation went sub 8:50 last year, and most only once in their high school career.