Getting started retrofitting a VMC with LinuxCNC, what is the Mesa roadmap?

I've taken up machining as a retirement hobby and last year acquired a full sized VMC for which I'd like to replace the ailing Semens acramatic controller with LinuxCNC.  That VMC uses Yaskawa servo controllers that can take either analog servo inputs, or step/dir inputs.   The spindle motor takes an analog 10V signal for speed control.    I am under the impression that analog servo control may work a bit better than step/dir, so it seemed that a Mesa 7i97 analog servo controller was a good option. 

Mesa cards have been challenging to obtain, and after checking their store site for about 6 months for stock, at the end of May I emailed them to inquire about availability.  I was told a new card was coming out to replace the 7i97.  I was recently contacted by them and told that the replacement 7i92TM was now available.  So I ordered one.  After reading a bit, it appears that 7i92TM would need a 7i77 break out board to handle analog servos.  The 7i77 is not currently available, so I contacted Mesa sales.  They placed the 7i92TM order on hold and have forwarded my email to their tech support, from which I haven't heard back yet.

So, I'm hoping for some help from knowledgeable folk that might suggest if a different approach makes sense, or do I just need to continue holding?
1) How much difference is step/dir vs analog control going to make for servos?  Should I consider using step/dir for the 3 basic axises, and work up some other solution for the spindle motor control?
2) Does anyone know what Mesa's roadmap is?  There isn't any clear indication on their website of what is going to be replaced, it just shows either out of stock or obsolete/replaced by for many of their cards.  It gets a little unclear what is supported by linuxcnc.  Obviously I'd prefer not to implement something that is immediately obsolete.  
 

I would try to use the existing drives and motors, they are very, very good, if they work.
If they do not, check what encoders the motors use, some are proprietary Yaskawa so trouble using those.
As for Mesa, you can find
7i96S+7i85S+7i83
7i92TM+7i85S+7i83
Probably will need more IO so adding a 7i84 to the first combo should take care of that, for the second combo maybe a 7i74 and 7i84 or any other IO card like 7i70 or 7i71 or 7i72.
Both combos will do for analog +-10V or step/dir with encoder feedback.

I would suggest either a 7I95T+7I83 (The 7I95T should be available in about 1 week)
or a 7I92TM +7I85 + 7i83 +7I84 (or 7I84D)

Thanks @tommylight and @PCW.    Lots of different ways of expanding these Mesa cards, l just missed this avenue in all the combinations.
I ordered a 7i92TM, 7i83, 7i84, and 7i85S  That should give me plenty of options to start with, and I can expand as needed from there.

You would want a 7I85 rather than a 7I85S as you need at least 2 SSerial
expansion ports and the 7I85S only provides 1.