The timing doesnt make sense to me.

We have future humans who have evolved beyond 3D and decided to save the humans through murph and cooper.

Are they from Edmund's planet and plan B humans? And doesnt their going back count as interfering with time?

Otherwise where did they come from? Because for cooper to be used he relies on tech built in the future when in the present plan A isnt feasible to send humans out to create the tesseract. And if plan A worked there'd have been no need for coopers plan.