While I was on the hunt for a good hotel for my bf and his mom, I frequently encountered receptionists who asked if the room would be for me, the Filipina. Apparently, they DO have different price schemes for foreigners and locals. The classier hotels say they have "discounts" for the locals, while others.. they just say it flat out - that there're different price schemes...
Can't say that I've any hotels to recommend, but given the choice, I'd also go for a short-term renting thing.
If you're gonna stay at Tagaytay, I recommend dropping by Bag o' Beans! Personally, i loved the ambiance and the food. I also heard that they offer accommodations, but... I wouldn't know about that. We usually just hit Tagaytay during daytime, and head home for the night. I've no email address for em, but.. their number is (46) 4132724.
Good luck to you! And a belated Merry Christmas