Access Peripheral via Python

I have a 4G WiFi Router using MT7620A with 1Gbit DDR2 SDRAM (W971GG6KB).
My questions are:

  1. Which version of OpenWrt is appropriate ?
  2. Which version of Python is appropriate to install on OpenWrt ?
  3. How to make Python know how to send AT command to 4G MoDem (on miniPCIe) and store its reply to SD Card?
  4. How to make Python know how to communicate with others device via UART or I2C or SPI ?

Please forgive me, I am new here...
I just learn Python and want to apply it on Linux Based OS for Embedded System.

Best regards

How much flash does your device have? Python generally requires more than 16 MB of flash, even with a custom-assembled ROM.