i havent read the guide you posted but in case it help you here is another guide.
this does work on rpi2 i am using it on almost 20 rpi2.
on post 24 or something you will find the guide for rpi2 and on last post scematics. Please remember i have forgot to use a rotary potentiometer at pin 3 of lcd for the contrast. The potentiometer has 3 legs. one leg goes to lcd pin one, one leg to lcd pin 2 and middle leg to lcd pin 3. on the picture i have it wrongly connected pin 3 to 1 with no potentiometer.
On the
Tell me if you need something. i think above you will find everything you need. follow the 1st post then read the second and make the changes it say and connect according to 3rd. on that same thread there is another connection diagram as a link somewhere but i could not see it.