I don't have any Kuwait specific information, but there are a few things in your question that I can answer.
The majority of the waiting time is for processing your I-129f petition in the US. The time for that processing is the generally the same, regardless of the beneficiary's country.
I'm sure the Philippine Embassy would have looked at her a bit strange, since her interview and processing would be at the US Embassy, not the Philippine embassy.
Yes, she will need a police clearance from Kuwait, and yes, she is eligible to get one. She will also need an NBI clearance from the Philippines. She will need both of these, no matter if interview is in Kuwait or the Philippines.
The Philippines processes a lot of visas and has a hospital that is very efficient for the medical exam. I do not know how efficient the process is in Kuwait. The potential down-side of medical in the Philippines is the approximately 10% chance of being subjected to sputum testing for TB, resulting in a 2 month delay.
The "2 day class" is CFO. It is actually a 1/2 day class. It is required for K-1's (and others) departing the Philippines. If she will depart from the Philippines, no matter where the interview was done, she will need this class. If she departs from Kuwait, not needed.
I would be surprised if Kuwait is significantly faster than the Philippines, but it could be. The only thing I can think of that might be faster is getting an interview appointment. That takes about 1 month in the Philippines. For Kuwait, it says to email them to ask for an appointment and they will respond within 1 day with your appointment. It does not say how far away that appointment might be, or how long it takes to process the visa and return your passport.
A conservative estimate for all of the processing in the Philippines, from the time they receive your case until departure, is 3 months. That is not 3 months from the beginning of the application. You have to add the US processing time and NVC time to that. For me, that part was 1 year. That's the time that you will wait before the case is sent to either country. It seems to be a little quicker now, maybe 8 months.
There is very little Kuwait data in VJ timelines. The 2 most recent K-1's took 13.5 months for US processing and 3-4 additional months in Kuwait before interview.