The requirements for the Saka-reform from the FAQ, which you should read in any case:
-You must hold Baktra, Marakanda, Alexandreia Eschate, Antiocheia Margiane, Alexandria Ariana or Taksashila for 4 consecutive winters.
This will enable new troops, most of them infantry. I'm not sure which in detail, maybe any other can answer that.

You have to clarify your second question, or if this is beyond your English, write it in French, I'm sure we've got native speakers on the fora.

XSamatan