The reason we have known the first generation of K-pop artists and groups since 1995 was because OCW (Overseas Contract Workers; as it was known then), and migrants, were bringing back albums to their kids and these were passed around in schools and friends. Some even hit radio stations; or were used as a music for the 90s Philippine dance craze.
In other words, long before the assumed beginning of the Hallyu wave, K-pop was already gaining grounds in the Philippines. Long before modern K-pop started to get popular in China and Japan, they were already known here in the Philippines.
I would say that BoA was the most popular K-pop solo artist in the Philippines because the Japanese versions of her songs gained quick popularity here, along with the original Korean versions.