Sigil: City of Doors

I don't know where to write this question I hope i choose the right section. Howver does half-dragon template class ability score bonus stacks with racial prestige class stat or both are based on epic feat?

Half-Dragon  IS  a racial PrC. And you can't have multiple racial PrCs as far as I am aware.

Yes, all the racial PrC stat boni are granted in the form of epic feats, I.E. 'Great Something + X'