Changing from Repetier to Marlin (7 replies)

Circumstances are forcing me to change from Repetier firmware to Marlin so I have been looking through the Configuration and various other files to get my system working. While I am very familiar with Repetier configuration I am finding a little difficult to find several things in Marlin.

The display is 20 character by 4 lines (HD44780 type) with encoder using 4 data lines, 'O.K.' button (push encoder) and back button
My pins are

LCD Display
RS Pin 16
RW Pin - (connected to GND)
Enable pin 17
Data D4 pin 23
Data D5 pin 25
Data D6 pin 27
Data D7 pin 29

Sounder pin 45

Encoder pins 37 & 35
O.K. button pin 33
Back button pin 31

SD card MISO pin 50
SD card MOSI pin 51
SD card SCK pin 52

Specific questions are:-

Q1) My LCD pins are the same as those in Marlins pins.h under ULTRA_LCD NEWPANEL. Are these what will be used if ULTRA_LCD is uncommented in Configuration.H and all others left commented out?

Q2) Where can I find the sounder (beeper, speaker) pin defined? In which file?

Q3) Where can I find the pins for the encoder, O.K. button and Back button? In which file?

Q3a) Is there a 'Back' button defined in Marlin firmware? Back here meaning back to the previous menu.

Q4 are those the correct pins for the SD card above?

Thanks for any clarification you can give.

Mike