Galio questions

More Galio questions. Do yordles inherent magic activate galio? If so that would mean that whenever Noxus attempted to attack Demacia Galio would always be there because because of Kled and Skaarl. Also would sion's necromatic orgins count as a magic source and if so would sion be able to even put a dent in galio? Final question would be how would hextech play into his activation process?