The workload for any AP depends, in part, on the teacher, but 60 minutes, IME, is not unreasonable for a non-lite AP class. 2-3 hours would be excessive, (assuming we are talking a year-long course meeting 5X/week)but we only have the other students POV and we don’t know if that 2-3 hours includes time that they take for breaks with their gaming systems. 
Sure, it’s central - history is a core subject. Is it a time eater? Maybe, but so are all the APs you listed. That said, if APEH really requires 2-3 hours for a student with strong time management skills, then I would avoid it.
Yes and no. Colleges will know that one HS has a reputation as being more academically rigorous than another. They will not know that Mrs. Smith’s APEH course is harder than Mrs. Jones’.
6-8 APs or equivilant over the course of 4 years is sufficicient. There may be valid reasons to take more, but not for admissions purposes. Additionally, no college is going to microanalyze the schedule by semester. So while one should try to space APs out as best they can, sometimes HSs limit the number/type of APs for freshman and sophomores.