Gk64 comes to mind:
- Wooden case option: check (KPrepublic sells this), not walnut I think
- Dedicated arrow keys: check
- Hot swap: yeah
Im not certain about the plate, you might have to buy a brass one separately. And I dont know about costa. You can ask kprepublic directly, they have good customer service. However, you are somewhat limited in the choice of keycaps, as the right shift is 2u and the left one is 1u.
Another option comes to mind:
Build from this pcb:
https://kbdfans.com/collections/60/products/dz60rgb-hot-swap-custom-keyboard-pcb- hot swap: check
- dedicated arrow keys: check
- Case: need to source from the great ali, any 60% wooden would do, just ask seller to be sure though.
- Plate and stabs: need to buy separately
- Wider choice for keycaps as 1.75U shift and 2.25u shifts are common. However, to get that right 1.75 u shift they ditch the ?/ key. Be aware.
- Price: yeah would be much more than than GK64.