It is not mandatory to have a lawyer. As long as you follow the instruction guide while putting together the application, you will not have any problem doing it yourself. I talked to a lawyer in Canada and she quoted about 7500 dollars which wasn't within my budget. I asked her how different it would be with and without a lawyer. She said that lawyers know exactly what the immigration officer wants to see. But I see that if you meet the eligibility criteria, and cautiously fill in the paperwork, a lawyer is not needed. Of course, it is up to your budget and your comfort. If you leave it in the hands of the lawyer, you will do all the paper work as directed by your lawyer, but whenever there is a problem with your application process, your lawyer will deal with the immigration officer on your behalf. In a nutshell, if your case isn't too complicated, then applying by yourself is advisable.
Regarding the employer reference letter, it is required that you submit it along with your application; check the document checklist. Request your employer to provide you with one. May be send him/her a format, so he wouldn't be bothered to draft one. Do you have a offer letter? your duties will be listed on it. If your employer doesn't agree to provide one, I suggest that you call cec call center and explain your case. I wonder how helpful it might be as their answers are strictly based on the document checklist.
May be anybody on this forum with a situation as yours might be able to verify your query more accurately.
