> Does this mean that this accounts for at most 2 OID requests with the following IPv6 addresses?
Yes, if you say you support 2 OID requests (i.e., NumNSOffloadIPv6Addresses is 2), then Windows may send those 3 addresses, packed in 2 OID requests. (You might see more addresses than 3, since Windows may send down the *previous* temporary address.) Windows won't exceed the number of OID requests that you claim to support, and you are obviously not expected to succeed any requests beyond the supported number.
> In other words, are we required to generate NA to NS requests for the temporary address?
Yes. This is actually particularly important for Windows 8 and Windows RT in connected standby.