I doubt you can use any other miles to book a PR flight aside from Mabuhay Miles. PR is not part of any alliance. 5J used to allow WorldPerks miles way back when but then it got downgraded and got banned from the EU so they got cut off from the redemption scheme.

Just book a flight with Zest Air, AirPhilExpress, or 5J. All these LCCs are so cheap that I wouldn't waste miles booking domestic flights in the Philippines at all.

If you're traveling within Asia, consider Spirit of Manila (out Clark), AirAsia, Tiger, Jet, or the above mentioned LCCs. Fares are cheap. Save your miles for something better.