For a multi-graft multi-species tree I think you would want to look at Krymsk 86. It has some good qualities. It’s much more readily available than Viking although not as easy to get as Lovell. Here are some links.
Do you have any grafting experience? Multi-species, multi-graft trees are pretty cool. But it isn’t easy to graft one and it requires more management when it comes to pruning, training, etc. I think it’s a worthwhile project but it may be overwhelming dealing with the learning curve if you don’t have any grafting experience.
@thecityman talks about the challenges pretty honestly I think and the rest of the thread has good info in it as well. One thing I will add is a tree like this is harder to spray because of all the different bloom and ripening times. In the Eastern US you will have to spray to control brown rot and to control insects.