Looking for the right trees
We are building a new house. So, there will be plenty of space, which we want to make look good and to enjoy it. The house will be East-West oriented in a pie-shaped lot and we will have a relatively big back yard at West and South. I want to create a mini forest in the West part of the yard. I was thinking of planting just pines (I love pine forest), but my husband totally disagrees, so now I am considering other alternatives.
I attached a picture with my project, so you can have a look at it. The space is roughly 35'x45'. I think to place an arbor with climbing roses, which will be the entrance to out "small forest". There will be a very small fountain in the middle, and a small gazebo at Northwest corner. And now - the Trees! I'll tell you what I have in my mind, but I will highly appreciate any comments about my choices. I must now state that I have neither knowledge nor experience with gardening. I just look in Internet and in the tree nurseries around and the more I read the more confused I get.
So far I decided that it will be good to have a round tree, a weeping tree, three columnar trees and a dwarf tree. Our hardiness zone is 5a, so, I was thinking about:
---The round tree - Autumn Brilliance Service Berry;
---The weeping tree - Weeping Katsura;
---The columnar trees - European Beech (Dawyck Gold, Dawyck Green and Dawyck Purple);
---The dwarf - Japanese maple shrub (haven't decided yet which one)
I think to add also some shrubs like Arctic Fire Dogwood and some small evergreens like small Junipers, Pines and Spruces.
Now I need your opinion and advice.
Do you think that a big evergreen is necessary in this case?
Do you think that there could be any conflict among all these plants?
Do you think that instead of three different columnar trees, it will be better if I choose only one kind for all three columnar trees?
What I look for is low maintenance trees (if possible), no poisonous tree parts, resistance to diseases, good matching in terms of ecosystem, and good matching in terms of beauty of course.
I'll appreciate any comments and advice, and I am willing to change any plant in the project with better one if it is necessary.
Thank you in advance for your help!