Magic: The Gathering

No, Yuna's second ability only triggers when another permanent you control is put into a graveyard from the battlefield. Yuna's own death does not trigger the ability, so you won't get to tutor or put cards onto the battlefield when Yuna itself is destroyed.

No, you cannot combine them. Per Magic rules, a spell can have only one alternative cost applied. With Lorehold in play, you can cast Cyclonic Rift for via miracle, but this produces the non-overloaded version that returns a single target nonland permanent. To use the overloaded 'return all nonland permanents' mode, you must pay the full .

No. When a saga re-enters with Doubling Season in play, it receives 2 lore counters immediately, which causes both Chapter I and Chapter II to trigger simultaneously on the same turn. Chapter I is not skipped, both chapters fire at once because the lore counters satisfy both thresholds together.

Tishana's Tidebinder targets the triggered ability on the stack (such as a chapter ability from a saga like Bahamut), not the permanent itself. Because that ability belongs to a creature, the permanent then loses all its abilities as a consequence of the ability being countered.

Urza's Saga's chapter-granted abilities survive Blood Moon because the effects that grant those abilities operate in Layer 6 (ability-adding), which is always applied after Layer 4 (type-changing, where Blood Moon operates). This is determined by layer sequencing, not by timestamp priority.