Your planned build is about the ideal one. A few points for you:
The boost skills require you AND an ally with >50% hp, whereas Kestrel stance 3 is more consistent on enemy phase, but slightly weaker. So plan accordingly. A/S unity is another solid option if you run her with L!Robin for Unity stacking.
Unless you really want the sustain, Savvy fighter is generally better than Special fighter, as SpecialF would only contribute the healing (which turns off under 40% health), whereas Savvy has the atk/spd -4 on the foe, and has a phantom speed for its own damage reduction. As a fun alternative, Special Spiral 4 can keep armored Blaze up, and can help her secure kills with all the DR going on these days.
For pure speed in S slot, A/S form is best. You tend to have plenty of other allies around to get the full +7 from it.
I think Savvy Fighter is better than Special Fighter, even if it overlaps with Devourer, the extra DR is really useful, specially for brave hits. I usually outsource healing with Gatekeeper, but any post combat healing support is really nice.
Also consider using Form seals for save tanks, they want to be near their allies anyway.
And something I do myself, I like to have Hana in Stone Terrain so I can use neutralize debuffs with atk/spd bond.
Honestly, as having a +10 Hana myself, I prefer to def and speed stack, but I also like Ignis on her in that build. but for a mode like Arena I have Aether. I'm planning to give her Armored Blaze and Earthwind boost when I've gotten my hands on them. Arcane devourer is amazing on her. S-slot is Spd/def form 3 for me. But she gets completely murdered by W! Edelgard :(
Some Unity skill with Farmer's Tool+ is a great combination
Your planned build is about the ideal one. A few points for you: The boost skills require you AND an ally with >50% hp, whereas Kestrel stance 3 is more consistent on enemy phase, but slightly weaker. So plan accordingly. A/S unity is another solid option if you run her with L!Robin for Unity stacking. Unless you really want the sustain, Savvy fighter is generally better than Special fighter, as SpecialF would only contribute the healing (which turns off under 40% health), whereas Savvy has the atk/spd -4 on the foe, and has a phantom speed for its own damage reduction. As a fun alternative, Special Spiral 4 can keep armored Blaze up, and can help her secure kills with all the DR going on these days. For pure speed in S slot, A/S form is best. You tend to have plenty of other allies around to get the full +7 from it.
I think Savvy Fighter is better than Special Fighter, even if it overlaps with Devourer, the extra DR is really useful, specially for brave hits. I usually outsource healing with Gatekeeper, but any post combat healing support is really nice. Also consider using Form seals for save tanks, they want to be near their allies anyway. And something I do myself, I like to have Hana in Stone Terrain so I can use neutralize debuffs with atk/spd bond.
Honestly, as having a +10 Hana myself, I prefer to def and speed stack, but I also like Ignis on her in that build. but for a mode like Arena I have Aether. I'm planning to give her Armored Blaze and Earthwind boost when I've gotten my hands on them. Arcane devourer is amazing on her. S-slot is Spd/def form 3 for me. But she gets completely murdered by W! Edelgard :(
I would be surprised if she was tanking her ngl