Are there specific mantras for honouring female ancestors in Tritiya Shradh?

Yes. The mantras for Tarpan and Pind Daan for female ancestors differ from those for male ancestors — they use the feminine forms of the lineage names and specific epithets for the deceased woman’s role (mother, sister, grandmother, etc.). Your Prayag Pandits pandit is trained in these distinctions and will conduct the rite correctly.