A.
(a) Yes, the quantity limit of UN1845 Dry ice is 200 kg. per package. Please refer to PI 954.

When dry ice is used for cooling other dangerous goods loaded in an ULD, per SP A151, the 200 kg per package limit does not apply. In addition, individual airlines have a dry ice loading limit such as so many kg (say 400 g) for the Forward Hold, and say 600 kg for the AFT Hold. Each airline has their own loading limit for the FWD belly and for the AFT belly of their aircraft type which must be checked in advance by the shipper.

(b)Yes, you can put up to 200 kg of Dry ice in the wooden overpack. If you need more dry ice, you will have to split the 10 boxes into 2 overacks each containing 5 boxes. You can then put 200 kg of dry ice in each of the 2 overpacks.

(c)The 10 boxes inside the wooden overpack can contain general cargo or other dangerous goods. It makes no difference. You may put maximum of 200 kg dry ice per overpack.