Connect I2C Oled display to MDSB42Q?

Yes, that should work based on https://www.espruino.com/SSD1306 - but obviously you'll want to change the pin numbers to the pins you have used.

You could also try:

// ...
var i2c = new I2C();
i2c.setup({ scl : D20, sda: D19 });
var g = require("SSD1306").connect(i2c, start);

which uses software I2C - either should work