Accomplishing part 2 can be done using 7-segment drivers (eg Max7219)
Yes, MAX7219 would have been my first suggestion also, unfortunately it doesn't support common anode.
I think the display driver approach is the way to go. I have such a board with 16 displays and it works quite well. I'm using one of the Maxim chips, I believe.
I don't recall if it is common anode or common cathode but considering the cost of the displays, I would scrap what I had if it wouldn't work with the driver. Displays are cheap, work-arounds for display drivers are ugly.
Since we're dealing with 70 inputs, I think I might be inclined to use a few IO expanders. Maybe something like the 16 bit expanders from Microchip:
http://www.microchip.com/wwwproducts/en/en023499. One expander to cover the 0's and 1's, another for the 2's and 3's, etc. Five expanders ought to do it.
Now the CPU only needs one SPI bus with 6 chip selects (5 for expanders and 1 for display). The inputs could be scanned or, I believe, there is an interrupt on change capability.