Japan's goal in WWII was basically a unification of Asia so it could be independent of Western "superiority". Also anecdotal evidence (mostly from my grandparents) says that the Japanese themselves weren't the ones raping and killing the captured population, just the Koreans who worked for them.
In regards to the "co-prosperity" sphere, suffice to say that the countries that were part of that during peacetime, namely korea and taiwan, came out of WW2 as some of the poorest in the world, even worse than african colonies and that's saying something.
In korea's case, as it's the best example of the loot and pillage methodology of japan, the per capita GDP was around $70. Comparatively Thailand was at about $210 GDP per capita and only India was lower than that at the time, but only because of the huge population difference. This despite the fact that the japanese exported an average of more than 100 million Yen in gold alone (official figures, but they're likely to be higher) from korea during the colonial era.
Given a japanese victory the only co-prosperity the philippines would've seen is the 'three-all' policies .. Loot all, kill all, destroy all. You and your grandparents should consider yourself lucky not to have experienced the tender mercies of the japanese for an extended period.
In regards to the smearing about the koreans being responsible for attrocious acts, the colonials (koreans, chinese, and taiwanese) were ordered to do the dirty deeds precisely so that naive and ignorant people would believe them when they claimed to be "innocent".
Even casual inspection shows that this is a load of steaming manure, I'll just quote two authors on the topic:
To the Japanese, Koreans
were only slightly better than the Allied prisoners. For their part, the
Koreans would have felt little loyalty towards Japan, which had invaded
and brutalised their country for decades. One Korean POW guard,
Kasayama Yoshikichi, said of his feelings toward the Japanese:
"After the first couple of years, we didn’t hide our feelings any longer ‘Do
you think we’re going to let you shit on us till we die?’ The Japanese
apologised and grovelled when they didn’t have their rifles."
One doctor witnessed three Korean guards attack a Japanese captain
in his sleep, and one of the guards repeatedly asked the doctor for poison
to kill this officer
from "More Complex than a Stereotype:
Australian POW Doctors and the
Japanese in Captivity, 1942–451", Rosalind Hearder
UTSUMI Aiko of Keisen University, Japan, conducted extensive research on Korean POW guards and found that more than 3,000 young Korean men were "recruited" (that is "press-ganged" or otherwise forced to "volunteer") for the prison guard corps. Many of [them] feared they would be shipped to Japan as indentured servants if they did not join the corps. Others were perhaps attracted by the high pay rates offered - 50 yen a month, a large amount at that time. [They] were classified as civilian employees rather than members of the military, and many hoped this status would prevent their transfer to the front line and ... allow them to be demobilized after their two-year contract was concluded. However, on joining, the new recruits were issued with uniforms, and their basic training was very much military in character, including weapons training. Despite the difference between the promise and the reality of the guard corps, few deserted, possibly because deserters were threatened with court-martial.
...
The Koreans were trained in Japanese and forbidden to use their native tongue. They were also given Japanese names in place of their Korean names. They were instructed to treat POWs as animals as a way of ensuring their fear and respect. They were trained primarily in the Japanese Field Service Code, and they were frequently beaten by Japanese officers, for no justifiable reason. The Geneva Convention was never mentioned. In other words they were trained as de facto Japanese soldiers, yet their rank of "kanshi-hei" (guard) was lower than that of a private, and there was no possibility of promotion. Clearly the Korean guards ... were treated as second-class soldiers within the forces, bound by the same iron discipline, yet enjoying none of the prestige accorded to Japanese soldiers. Indeed, one of their unstated functions ... was to give the Japanese soldiers someone to look down on, thus strengthening a sense of ethnic solidarity among the Japanese and minimizing the resentment felt by Japanese troops toward their officers.
from Hidden Horrors: Japanese War Crimes in World War II by Yuki TANAKA
Note specifically the phrase "They were instructed to treat POWs as animals". And refusal brought about a firing squad or beheading. Placed in such a situation there's not many people who'd choose death.
Although I don't discount that some may not have been as coerced, blanket statements scapegoating koreans especially (taiwanese were also treated the same way but to a lesser extent) like you have is exactly what the japanese intended when they conscripted koreans .. patsies that could be put up to take the fall, despite the fact they had no choice. Suffice to say that you'd have to be incredibly naive or partisan to believe that they did not have complete control of what was carried out in their name.
Given the racial superiority views that the japanese lived under at that point it would surprise if they were to treat the philippinos as well as that .. if anything worse.
You should count your lucky star that you live in a world where you're not part of a "co-prosperity" sphere under japanese guidance instead of believing the propaganda either out of ignorance or fanboyism.