iMac and connected external displays, all as monitors for MacBook Pro?
Short answer:  No, this can't be done.

At the very minimum you would need to set your iMac into "Target Display Mode."  The last iMac that will support this is the Mid 2014.



Now, if you happen to have a compatible iMac (not the "newest model" you referred to), it still wouldn't work.  Target display mode turns your iMac display into an external monitor for your compatible MacBook with a Thunderbolt port.  It doesn't turn it into a "thunderbolt hub."

I am assuming you don't want to use the iMac and instead just use your MacBook and your goal is to get three monitors going...  I suggest just getting a third monitor and hooking that up to your MBP and bequeathing your latest iMac to a worthy coworker.  I am a huge proponent of finding the simplest solution and not layer it with complexity.