Which combination of mesa cards should I use?

I have an existing SBZ 130 i want to retrofit by keeping the original motors+drives, the motors all (3 axis and spindle) are AC 3PH servos with integrated 2 pole resolvers (6 wires - sin, cos, excitation pairs) for their feedback, aside from that I have about 42 inputs and 36 outputs as per the machines original schematics, but I might not use every single one. Moreover, I also want to add a separate rotary milling head for chamfers at different angles later down the line, so how would I go about adding/changing the combination of mesa cards.
The same machine I've seen a successful retrofit using combination of 6i25 7i77 7i70 7i71 7i74, but that system all the motors had absolute encoders
Mine is slightly different model (1998, mine is 2001) and I was recommended from a different person to go with 6i24 (do i need 6i24-16 or 25 and whats the difference??), 7i49 for the resolvers and controlling the drives with 10v analog, but would this work? I'm a complete beginner to this field so I'd like to know before purchasing any hardware. Moreover, do I need the other cards as well? (7i70 7i71 7i74) I understand the first two are for extra I/O digitals but im not sure what the 7i74 does, if someone can explain I would greatly appreciate it.

Edit : I just found out that the 6i24 has about 70 I/O pins, I think that covers my need so I dont need the extra 7i70 and 7i71 right?

If the resolvers connect to the drives (expected with AC servos) ,
a 7I49 is not needed (or useful)

I see, so 7i49 is meant for standalone resolvers yes?
also in that case could you let me know what combination I can try?
my teammate on this project has requested the same information on another thread, along with some other documents and images that might help
forum.linuxcnc.org/30-cnc-machines/31792...1-retrofit?start=150

we're both interns working on this project with no experience, completely fresh to the field, so help would be greatly appreciated.
Thanks!