I will go through your ?'s in order:

A.A fescue grass would be the way to go.  It will still need at least one nitrogen application per year and some watering.  Dutch white clover can be mixed in as well.  Yes, a broadleaf weed killer used to kill dandelions etc , will kill the clover as well.  Fall is the best time to plant a lawn, spring... second best.  The seed must be kept constantly moist for it to sprout.

See: 1.canr.msu.edu "low maintenance lawns in the Midwest"

2. cloverlawn.org

B. The common violet is often seen in lawns.  It can become invasive as it spreads from underground roots and seeds.  Once it is established, only a strong weed killer will deal with it.  You could grow it in borders and watch that it doesn't spread to the lawn.  You cannot "toss" wild flowers like trillium into the lawn.  Grass needs sun and would crowd out trillium which grows in partial shade.  Trillium would be a good border plant.
***  Before I continue... each plant has requirements for success:light, moisture, soil nutrients.  In order to be successful, you will need to plant them in the right places.  I will include some websites which list plants and where they are happy.

C. Native species or older plant varieties are often better for bees and butterflies than hybrids which have been developed for showy flower which often don't have as much accessible pollen. If you are in the city, you may need to plant things that feed the caterpillars which will then produce butterflies.  If you do see butterflies around, then pollen/nectar plants will do.  (read David Suzuki's article)( also MSU site)

www.davidsuzuki.org" How to create a pollinator friendly garden"

Select Eastern Canada(similar to MI), then browse the Toronto plant list, noting the growing requirements

 From Michigan State: pollinators.msu.edu  "Pollinator gardens"

a few suggestions: butterfly weed, swamp milkweed, butterfly bush,ninebark(a native shrub) bee balm(both native and hybrid) mountain mint(will spread but easy to control unlike herbal mint)

Where to purchase plants?  Now that we are in the heat of summer, I would wait until the fall to purchase and plant any tree or bush.  The time to order/buy smaller plants is in the spring. 

Or do you have friends which need to divide some plants?

Look online for native plant nurseries. Some may be near you. Local garden centers  have begun to label some plants which attract bees/butterlies/hummingbirds. In some cities, organizations have plant sales in the spring.. garden clubs, local gardens.  There are also numerous online nurseries.  They offer a wide variety but the more popular items are sell out quickly.  In my experience, the plants are in good shape when shipped but are small.

the Clinton County Conservation District has an annual plant sale every spring.  You can get on their mailing list so you will be notified.  The smallest numbers of plants you can buy is 5 and they tend to be inexpensive but very small.  This year I noticed they only offered trees.  Ask if they are having a plant sale next year.

be sure you have studied the cultural needs of what you plan to plant...

D.  The Clinton Conservation District offered "canoe birch" this year.  THis is the tree with the white bark.  I find this interesting as Michiganders have been discouraged from planting paper birches because of borer insect problems.  Perhaps the "canoe birch" is resistant?  It is worth asking.  The most popular birch at the moment is river birch.  it has interesting bark.

About Growth Rate

“Rate of growth refers to the vertical increase in growth unless specified differently. Rate, as is true for size, is influenced by numerous variables such as soil, drainage, water, fertility, light, exposure, ad infinitum.

“The designation slow means the plant grows 12” or less per year; medium refers to 13 to 24” of growth per year; and fast to 25” or greater.

    You can learn the growth rate as you select a tree(s). Be mindful of the mature height and sun/shade, soil, moisture requirements.  A newly planted tree will need its root ball moist and the immediately surrounding area moist as well so the roots will expand.  Depending on the size of the tree and rainfall, you may have to supplimently water for 1-3 years until the roots are established.  This includes making sure that the tree goes into the fall/winter well watered.  (shrubs also)

One of my favorites is a service berry, a midsized tree with pretty flowers in the spring and bird/people friendly berries following.  Also a nice fall color.  

E.  canr.msu.edu  "Mulch. Just Do it!"

For a specific bed, stones and shredded tires are ok and have a specific "look"  They do not contribute to the organic matter in the soil.  Shredded or chips will break down and contribute to the organic matter, encourage increased microbal activity in the soil(a good thing) and look natural.  Shredded bark will break down faster than wood chips.  Again, the look may be important for you.

Whew.. this is a long answer but you asked some good questions.  There is no such thing as a maintance free landscape... It goes up from there.  I would concentrate on your lawn area and maybe a few trees/bushes.  Add a few plants(groups of 3 is good) but not too many and access how much work you have before you go crazy on plants.  Mulch early in the growing to stay on top of weeds which is the greatest maintenance problem in my view.  Above all , have a lawn chair in the shade, a cool drink and enjoy your yard.