Planting & design ideas needed

My new hubbie has finally decided that the thornbush can go! We live in the country on a slope. He has left the thornbush grow for years for a privacy fence out front. The area is about 85 foot long and is mostly 20 foot wide.
We are leaving 3 very tall trees (hemlocks, I believe) that stand from one end to the middle and we'll be putting up a fence that will be right at the back of the trees. That will be the only shade in the area. This area will be the only level area we have.

I won't post any pics yet, as it is only halfway cleared. But here is what I have in mind. I want to have a pathway through there of flagstone (?) lined with bricks as hubby has tons of them. I want to have a fire pit at its widest with a seating area but with the path in between. I want the seating area under one of the trees as this is the only shade we have in our yard. The area is south facing and I live in western NY (zone 5). The opposite end will have no shade but it does have a very sharp bank from our yard to this new area.

I have already purchased 2 jackmantii clematis. I would like to plant them near the fence but wonder if they will get enough sun to start off (fence will be 6 foot high). I've read where they like there feet in the shade and their head in the sun, would they do ok there?

We don't want to mow any of this new area. Plus I would like plants that bloom most of the summer. I've tested my soil and its A+. My budget is about $800 over the next 3 years for plants. I don't want plants that will get nuts and take over. I've been doing battle with irises that were previously planted at another location (they are as bad as the weeds!).

I would love any suggestions and plant ideas as I have so many...LOL.

Will try get back to you re planting plans and ideas.
For now, you are correct re the conditions for the Clematis, they do NEED roots in shade and tops in a bit more Sun, NOT blazing hot sun as the foliage will just burn and shrivel.

You can still grow the Clematis and have the fence as the background. I have a climbing Rose (Yellow April showers) and clambering up this is a lavender coloured Clematis, it really is quite stunning when the clematis flowers and the Rose is still flowering it's socks off. BUT I have these growing up / over a wooden Rose arch, I have just bought a good strong metal Obelisk frame, and am looking to plant that up with more clematis, IF you wanted this style, all you have to do is bring the Obelisk forward into better light and plant the roots in the back of this where it will get more shade, slant the clematis towards the frame. A flat stone laid on top soil is another way of protecting the roots from hot sun but make sure the stone is NOT constantly stood on, Clematis need lots of Humus added to the planting hole and dug into the soil, make the soil ready well in time for the plants to be placed in situ, Horse manure is the best humus, well rotted, it should have no smell, most places who have horses allow you to take the manure for free. these plants also like lots of watering in the growing season to get them started growing well.
Hope this helps out a bit.
Kindest Regards.
WeeNel.

Thanks so much for the tips. I was thinking of maybe planting coral bells over the roots of the clematis to help keep the roots cool. I've read where you can use caladiums as well, but they are not hardy in my zone. I'm hoping to get them into the ground soon.