What I think you're saying is that you want to mount a Sunrace DT shifter on the Shimano bar end mount.
I doubt if you can. I know that there is incompatibility with Sunrace DT shifters and Shimano DT shifter mounting hardware and I suspect it is the same for bar end shifters.

Why change to 10 speed? 8 speed cassettes and chains are so much cheaper, and, longer lasting.