Thank you,...presumably I will get no more updates in the future?
If I were to purchase a new iPad,could I have two iPads available, the old with with its current apps/photos and the new with future apps/photos and also becoming my email device,using my existing Apple ID/Access on both devices.
Would I be able to connect either device to my iMac?
Yes to all your questions! I kept my iPad 2 when I bought an iPad Air 2. They, together with my iPhone, all work happily with my MacBook.