I joined coins ph because of there free withdrawal @ATM but this service is not available and no information for how long.
This might be the best way now, btc > coins btc wallet > coins ph > gcash
but for me not ideal. you get a bad price for the conversation + the 2% fee to gcash. at the end you have to pay about 4-6% (included conversation).
With GCASH, the fee is 471 php that's quite a bummer.
With LBC, the fee is only 120 php.
Or you can try sending it to your bank account with no fee at all. There were some banks that I tried months ago that has no fee. Goodluck!