1. I am using nokia 5110 lcd, with arduino uno r3 & v1.6.5
2. I have below libs & they worked both fine:
http://playground.arduino.cc/Code/PCD8544
https://learn.adafruit.com/nokia-5110-3310-monochrome-lcd/downloads

3. Currenly I am using first library.

4. Now MCu works at 5V while lcd is at 3.3V. So I need a level translator.
However instead of shifting level, I have connected 10K series resistor at reset, cs,dc din, & clk pins.
is it ok to do so or I need to connect a level translator.

5. Vdd lcd = 3.3V via arduino board.
5K pot at BL pin of lcd, for adjustment.

 

Since the display needs to be buffered that implies you will never read data from it, just send data to it. That is simple to do with a voltage divider made from two (not one)resistors. I expect these to be CMOS type inputs with minuscule currents but do check that. If so, something like a 20K/33Kdivider should be fine.

Do test the logic levels before you install the LCD to prevent any damage, and test again after install to make sure they are still acceptable.

If you want to read data back from the display it gets harder as you need a bidirectional translator for the data lines. That is a lot of trouble for a feature you do not necessarily require.