Kyushu Island recommendations please!

I'm an avid solo traveller to Japan but I will be heading down south to Kyushu for the first time this upcoming January and would like to brainstorm all the main attractions.

I also do not drive. I am not opposed to seeing gardens but please keep in mind that I am visiting in January and most things will be dead. I am also a huge fan of shrines / temples / unique architecture.

So far I have:

NAGASAKI:

• Nagasaki champon (to eat)
• Atomic Bomb museum
• Gunkanjima (not sure if weather will permit)
• Mt. Inasa

SAGA:

• ?

KUMAMOTO:

• Kumamoto Castle
• Kumamon Square / Luffy statue (I like both)
• Mt. Aso

KAGOSHIMA:

• Sakurajima

MIYAZAKI:

• Aoshima

OITA/BEPPU:

• ?

FUKUOKA:

• Kushida Jinja
• Uminonakamichi Seaside Park (not sure if anything is alive in January?)
• Canal City

I have about 1-3 days in each prefecture (flexible) and am happy to explore cities in-between as long as they are accessible or close to any stop on the All Kyushu JR pass. It's looking a bit bare right now so I'd love some help fattening it up!