Yes Red did say 4K for $4k a long before Blackmagic. That was before Scarlett was released. Red failed to deliver that time and Scarlett ended up far more than $4k
Sure you have, like this shot on FS7https://vimeo.com/119020133
$1600 makes it cheapest FF camera (launch prices, not street prices) in history. This is still camera, not A7s that was optimized for video quality.
This is cheaper still camera first, and video quality obviously won't match A7s that does full sensor readout without line skipping.
Second, as for inbody image stabilization, it works with every lens, as long as the camera knows the focal length. If you have a dumb adapter that can't communicate the focal length to the camera., you have to add the focal length manually from the menu.
So yes it should work with all lenses, one way or another.
It was typo of course. I meant 600 Mb/s. You don't need 400 MB/s cards for that. 600 Mb/s only needs 75 MB/s cards. If safety margin is required, S series cards that does 160 MB/s should be more than enough.
Test it before believing stuff. FS7 max is 60 Mbits per second. You shouldn't need 400 MB /s card for that. I bet it works fine with 100 MB /s cards