Multiple Negates - Raiho/Murakumo/Bagooska

If my opponent has both General Raiho of the Ice Barrier and Ame no Murakumo no Mitsurugi on their field, and I activate the effect of Ice Ryzeal on normal summon, and my opponent chains Murakumo to negate, can I choose whether to discard for Raiho or for Murakumo? How is the order of these negations determined?

Likewise, does it work differently with mandatory negates like Bagooska? If my opponent also controlled Bagooska the Terribly Tired Tapir, from which their Raiho and Murakumo were somehow protected, would the order of application place Bagooska's negation last, or are Raiho and Murakumo's effects simply ignored in this instance?

Thank you.