You really want to handle all cameras mentioned, put your lens on them. the size of the 1series and weight might not be for you,conversely you might find the balance with the siggy works better for you. with a 1series brick(sorry body)
The AF is such a big deal for BIF,I really think the only way one can assess how suitable that AF AF's is by trying some camera bodies physically.
Cathy bodies loose value,because they are replaced by the new latest greatest so frequently, so
second hand does open options. with 2K my deliberations would be 5div or 1dx,but that means little to you. Just remember that the one series really are built like a tank,for a pro to use and get his/her image in what ever conditions,they really are built to last,I use a much older 1Div,in good light it's
Cathy,my biggest and only real reason to post here is to encourage you to get hands on before you buy , you might adore a 1 series it might be too heavy,too big,only you can tell that,you need to try them mate,I'd go to a good shop like LCE,you could probably arrange to try most of the bodies mentioned here
second hand and new(I'm sure they'll get them moved to a store of choice if needed and see what you really feel suits you best
all the luck
stu