Do your dogs eat plants? Most dogs will not eat plants in any quantity and if you only plant non poisonous things, you greatly limit your choices. If your dogs do eat plants, please check with your vet before planting anything. Plants that are non poisonous for humans may be poisonous to dogs.

Before choosing shrubs and trees, make a note of the soil type (sand, clay, loam), moisture levels, shade and sun levels of the various points in your yard where you want to add shrubs. Also note the size of the area, other trees or houses nearby, consider maximum acceptable height and width of plants for each area. Finally note where North is on your lot. Plants to the north of new shrubs will receive all day shade after the shrubs are planted -- make sure they can take shade or be prepared to move them.

Consider how many shrubs you can add and what features you want. Do you want flowers, fall colour, edible fruit for humans or birds, fragrance or ....? Some shrubs have many things going for them and all season interest, others are interesting for only a week or two during the year. If you have a large property and room for lots of shrubs then the latter type can be considered; if you only have room for a few shrubs you will want to make sure that every one is doing double or triple duty.

Now make a list of what goes where ie dry, shade 10ft tall in this spot; moist,full sun, 3ft tall in that spot. Consult shrub books from your local library (Ortho series are very good) for lists. Then check the characteristics of the shrubs in the list for fruit, flowers, colour and so on. Now pick the ones you want. Remember, it is better to choose several on one type planted together rather than a hodge podge of many different shrubs.

Sounds like work, but a mistake will be costly.

As to the ones you asked about:
Dogwood: Flowers in late spring, berries in summer, good fall colour, attractive winter bark

Mock Orange: fragrant, attractive flowers for two weeks every year, boring the rest of the year.

Holly: Evergreen for the winter, red poisonous berries on female plants, may winterkill in Zone 5, needs acid soil

Hawthorn: small tree, pretty flowers in early summer. May lose leaves in late summer due to fungal leaf disease.

Bridalwreath Spirea: pretty white flowers in June, otherwise not very interesting. Can be used for hedges.

A good list of shrubs is below

Here is a link that might be useful: Shrub Table