Picea mariana (Black Spruce) might fit the bill for the new tree. Native Plant Trust lists it as a "pollinator powerhouse plant" among other wildlife benefits.

As for shrubs, Lindera benzoin (Spicebush) has yellow early spring blooms and is a host plant for a number of species - not least of which is the Spicebush Swallowtail butterfly. It's not going to provide you any privacy but my favorite plant, Ceanothus americanus (New Jersey Tea) is also native to the region. Michigan State's extension office has three lists of native plants depending on your specific region of MI with consideration given to the different soil types throughout the state.

Laurels (Kalmia genus) are evergreens with cool flowers. However, they're highly poisonous if eaten so not good around curious kids or animals.

https://www.wildflower.org/plants/result.php?id_plant=KAAN

Witch Hazel can take a few years to bloom and the leaves can look raggedy with all the insect action. But I did see a witch hat gall this summer which was really neat!

Spicebush could be an option. Black chokeberry too, it has awesome fall color.