donation of property

My father passed away last Sept of 2017. We already have filed his estate tax to BIR. My mother decided to waive her rights with the property and have it divided among me and my siblings. The EJS that we filed also contains her waiver of rights to the property.  We already have our lot surveyed and divided into 3. TD's for the 3 lots are already made but not yet registered considering that we still have to go through the process of transferring. We also have a notarized deed of partition and we are currently acquiring the certified true copy of the title. Anyway, my question is since my mother have waived her rights to us thru the EJS will that be considered already as a deed of donation? And if yes, is it already the start of the process of transferring the property ? Or we should file it separately from the estate tax ? I'm kinda worried that we should already be paying for the donor's tax & doc stamps or we would be penalized if we failed to pay for it w/in 30 days the EJS with waiver of right was notarized. Hoping for your advice. Thanks in advance.