Display with and whithout i2c


I want to know how can I use in a arduino project, 4 displays LCD, but two displays have the I2C board and the others do not have.

I would say just go buy two more i2c LCD backpacks. They are less then $1 USD shipped to your door.
That way, you can use a single library which saves flash space and you will only need 2 pins control all four LCDs.

(I'm assuming that you are talking about hd44780 LCDs)
--- bill