I just wanted to say the second image from the top is my favorite. The lighting is great, its interesting tho in some of the other renders it seems your going for a night time type render considering the large moon in the background but the sky is saying dusk or dawn. Maybe try to find specifically a night time HDR for the sky.
As far as the trees go your showing great use of the snow feature:) In terms of repetition I don’t think its bad may just make sure you have random rotation using Global Z. This should make the trees straight up and down and allow for randomized rotation. You may already have this set. If you post some screen captures of the particle system setup I might be able to help more.
The only real comment I might have it the snow. I think you need more subdivisions and some displacement with some bump especially near the front door. Maybe try to get some sparkle too by using a small noise texture to control reflection value or emission even to trick the camera:)
I love the architecture of the building and the material choices:) Keep it up man nice job.