Hello!
I'm not sure your project meets the CL legal use, but I think I can still help. I believe it is possible to write an application that does not rely on any web browser, so deleting cache will not be necessary.
Additional questions:
1. Do you want a graphical interface? Or can this be a simpler command line tool? You can then use Windows Task Scheduler to handle the scheduling. This would make things much simpler. If you do want a GUI, how do you want it to look?
2. I'm not too familiar with CL "renew" is it enough to just "edit" a post, but make no changes?
I have many years of professional development experience, and I think you will be pleased with the result once we establish exactly what you want, and if it is feasible, given CL restrictions.
Thank you for your consideration,
Eyal