Is F1 to H1 change of status possible (for my case)?

[venkat5121]

This is my unique case and wanted to know any experiences or suggestions that I need to make sure. Thank you, everyone, in Advance.

My H1 6-year cap is expiring this Jul-2019 and my employer(Full time & University) is willing to start my GC process.
I am also halfway through my Masters in the same university which I am doing evenings(not to affect my Fulltime employment) and have a chance to go on F1.
With current timelines, I may get PERM approval between Dec-2019 to Mar-2020.

1. Can I go on F1 now, be on part-time, till my I140 gets approved?
2. As I will consume all my 6 years on H1B, Will my employer be able to file Change of Status - F1 to H1B next year - with my then approved i140 or will it become a fresh H1B petition?
3. If I convert to F1 by this May leaving some 2 months on my H1B 6year cap, will my employer be able to file the change of status - F1 to H1B next year - along with a valid i140?
4. Instead of being on part-time during this time, Can any OPT or CPT will allow me to be on full-time employment?

Consider my employer is with me, supporting all through this process and I have no audits/denials whatsoever.