Help with planting ideas!

Hi all
First post and new to gardening etc but learning a lot fast. I have just landscaped my back garden with the aim of making it more manageable. What I have left to allow myself to plant is 4 beds, two at the front of our decking either side of steps and two to the side, approximately half way down the garden. Please see the attached plan, i hope that its clear enough?!
We did the work on the garden as we are looking to move within two years. Because of this reason we don't want to spend too much on plants we will have to leave behind but will spend a little more on a few specimens we can take with us. What we have been drawn to so far are Acers, cherries, magnolias, slender trunk Hornbeams that we could either pot and place above ground or leave potted but dig them into the beds. As far as plants we would leave, we are struggling, but one idea was to create wild flower beds with varying heights. We thought of this as an economical option but also because we genuinely love wild flowers and it would be wonderful to see some local wildlife visit our garden. Should I be wary of anything in particular with wild flowers?
I should mention that the garden is S.E. facing and mostly clay alkaline soil (which may be an issue with the magnolia).
Like I mentioned there is a plan attached and we would love any input!
Thanks for reading and look forward to feedback
+-------------------------------------------------------------------+ |Filename: garden online plan.pdf | |Download: 964| +-------------------------------------------------------------------+

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