Larry, this is a reddish flowered type. The white flowered ones are less interesting to me. Maybe others disagree.

Proper tree trimming/pruning is not a bad thing. In some situations it can be necessary for various reasons or even beneficial to the tree. A practice called topping (a.k.a. butchering a tree) is harmful. I'm not sure what you are looking for here, but the site linked below is an extremely valuable resource. I am linking the "Pruning Mature Trees" page, but there's also lots of other good informative articles available on the site. Here is a link that might be useful: TreesAreGood (ISA site) - Pruning Mature Trees

I've seen lots of DDB, it is a popular landscape tree in the SE. I've only seen one EB, my tree. EB's main claim to fame is it's supposed hardiness. Mine is in full sun and wide open, no large trees anywhere near it. It is about 20-25 years old from a one gallon. It is wider than high, branched to the ground, and fairly open with somewhat long willowy branches. It took a long time to bloom, and is even now a rather shy bloomer. Blooms are of average size. For me EB has been of average hardiness, it has never lost any wood or suffered any bark split, but it has had browned foliage, though never defoliated. On a scale of 1-5 I rate it 3. DDB is very popular and often seen in private landscapes and especially public ones. It is upright in youth and more spreading as it ages, but taller than wide. Foliage is deep glossy green above and copper/red beneath, especially when young. The tree presents a lush, rich appearance and is a vigorous grower. Floriferousness has been average, but blooms are well formed and slightly smaller than average, a good thing IMHO. Hardiness has been on a par with EB for me, the literature says less hardy than other hardy clones, zone 7. On a scale of 1-5 I rate it 5. All magnolias grown under conditions you describe will tend to be open, with slightly larger than average foliage and less than average bloom, all due to shade. If DDB and EB are the only clones under consideration, my choice would be DDB.

There is absolutely no reason not to plant it now. As to how close to the house should you plant it, that depends on how you want to configure the shade qualities it will eventually produce and on its mature size. Depending on species, most sycamores can get to be very large trees with wide spreading canopies. Typically, you would not want to plant any closer to the structure than half the expected mature canopy spread but calculating shade production may increase that distance. You can check online for formulas to help you with that calculation. There is no need to do any pruning at this point so I'd suggest you read up on structural training for shade trees to know when to begin and how to go about it. This link should be very helpful in that regard. And for clarification, sycamores will develop a decurrent growth habit so focus in on training/pruning methods that address that characteristic.