Hi Asivad/Raj/Others,
Q1) I have got a couple of questions regarding my work experience. My current score is 478 so I am not sure if I should accept ITA if I get one soon.
My work experience is as below:
1.Graduate Teaching Assistant(USA)--Part time(20hrs/week) -- (September 2012 to May 2013 and August 2013 to May 2014). I didn't work in June and July as it was summer during school. I have read in FAQ that I cannot count teaching assistant experience under CEC but it doesn't say anything about FSW. And the requirement for being a TA/RA is one should be enrolled in school. So I am counting this experience also.
2. Associate RF Engineer--Company A--June 2014 to December 2014. Full time.
3. RF Engineer--Company B--December 2014 to current. Full time. Same NOC code as of Job-2.
I am not sure how the tool calculated my points but I am currently standing at 478. I have about 2 years of full time experience and about 19 months of part time experience(different NOC). 
AFAIK, work experience gained in Canada while you were a full-time student doesn't count. My take is that this does not apply for people who have gained work experience while being a student outside Canada. 
I guess you would have chosen NOC 4012 - (NOC A Category). Under that, I am able to see the following titles - 
	
	
		
		
			college laboratory assistant
    college teaching assistant
    demonstrator, laboratory – post-secondary teaching assistance
    discussion group leader – post-secondary teaching assistant
    graduate assistant – university
    laboratory assistant, college
    laboratory assistant, university
    laboratory demonstrator – post-secondary teaching assistance
    laboratory supervisor – post-secondary teaching assistant
    marker – post-secondary teaching assistance
    post-secondary research assistant
    post-secondary teaching assistant
    research assistant – post-secondary
    research assistant, university
    teaching assistant – post-secondary
    teaching assistant – university
    teaching assistant, college
    teaching assistant, university
    tutor – post-secondary teaching assistant
    university laboratory assistant
    university research assistant
    university teaching assistant
		
		
	 
Further, if work experience gained while being a RA/TA was not allowed, then CIC would have mentioned that this NOC is not applicable for people applying under EE. 
So, IMO, I guess you can add up the part-time experience you gained while you were a student.
Check this link below - 
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=855&top=6
This further reinforces what I have said above.
Q2) All my previous employers are willing to provide me letter of employment with all the required details. However, I don't have pay slips from previous employers. Do we need to submit pay slips for all the years or will the most recent ones will suffice? All my employers are helpful and are willing to provide all sort of documentation needed to prove my employment and annual salary.
Payslips are not mandatory. As long as the reference letter mentions all the details as required by CIC, you wouldn't need further documentation.
Q3) For proof of funds, do I need to show monthly statements with balance of $12000 CAD for past six months. My monthly balance has been gradually increasing from $8000 CAD and now its around $15000 CAD. To supplement this amount, I can show my bank statements from my Indian bank accounts. Please advise what would be the best thing to do in this case.
 If you can get a letter from the bank that mentions the average balance for the past 6 months, then, you wouldn't need to submit 6 months statements. Otherwise, you need to submit 6 months bank statements along with a bank letter. 
I appreciate it a lot if you can reply to my questions. Thanks!