Deckel Retrofit FP4A

Yes. I created cart on www.eusurplus.com . But asking should I wait for 7I77 or just go for same combo?

The reason I choose the five board solution for my lathe, was because I knew I would want multiple smart serial daughter boards. (At least one 7i84, and one, probably two 7i73's). The 5i25 would need a bit of firmware configuring to connect up further SS to it's pinhead connector, to expand beyond the single SS channel of the 7i77, whereas the 7i85 offered 5 SS channels as it's default config.

The Mesa hardware is very flexible, so you can achieve your goals with a number for different cards. I am considering even adding a second 7i84 to the lathe, as I ran out of 24V outputs.

So, while i am waiting for MESA hardware, i have found out that Linear encoders are plugged into Dialog control. 

I have found board: 
Heidenhain 255 180 ZY. I would prefer this one over EXE unit. My glass scales are Heidenhain LS904. I think this is compatible with the Platine?  

The LS904 output their analog sin waves:
product.heidenhain.de/JPBC/image/HWP.DE/...06-92_ls_804_904.pdf
You will need EXE's to do the A/D conversion before inputting the signal to the Mesa. Whether you use a three axis EXE board like the one you mentioned or three individual ones is only a packaging issue. On my Maho, I had a similar three axis EXE. One channel was dead, and one was unreliable. I now use the one functioning channel, and two stand alone EXE's.

Those three axis EXE boards are three completely separate channels. There is no electrical connection between them, Not even the supply power or ground are common.