questions about open circuit, pull up resistor and MOSFET selection
First answer is here: 

See a picture, you can also check datasheet, to check about capacitor connection.

Second: Placing larger pull-up resistor value will reduce current, so it depends on you and where you are going to use it. But it is not wrong if use any value between 10k and 1M.

You can not use any MOSFET (it is connected to 3.3V through pull-up 90k), you need one that can be controlled by Vgs&lt;=3.3V.