For the display it is easy - use GPIO2 and GPIO3 (PIN 3 and 5) for I2C
I also use the “cheap” display. It has I2C address 3C but supercrab’s plugin let’s you check for that.
The encoder - i can tell you on Saturday how i did it - i do not have the device here and unfortunately no docu on it, but it’s working very reliable with the 100nF capacitors in place like described on Saiyato’s github page.