I dunno. I feel like the constraints you've provided are rather arbitrary (and some of your claims easy to disprove). If you really want to list PC Engine originals, you need to exclude anything that has a version on another platform, even decades later, if that other version is nominally the same game. Which is to say, the only true PC Engine originals are those games for which the core experience can only be had on the PC Engine, and not some other system or platform, before or after.
Regardless, if you want help constructing a list of games meeting particular criteria, you need to make sure you are being specific in the details of your request, and when those details seem odd, clear in explaining why those criteria are important. Basically, if you want our help you need to tell us why we should care.
