1 - Yes it is part of it. If you can get new one than it should be in English, if not then get it translated and make an affidavit. At the time of invitation you should also send photocopy of Original BC along with translated affidavit of BC.
Alternaive: If you do not have Birth Certificates than 10th mark sheet will work as long as it has Your Date of Birth, Mother's Name and Father's Name with a Letter justifying why you are using 10th Mark-sheet (Your country was not issuing Certificates at that time Or you do not have have it some how.)
P.S. Try to get BC, if not possible then go with alternative.
2- No specific format for POF. Say for example you are single. So you need $12000 (rounded up) for POF. Below is how it will work(taken current month as submission month and supposing that your are providing Bank statement as POF for last 6 month):
Oct - 2014 $8675 Available balance in $ at end of every month
Nov - 2014 $9477
Dec - 2014 $10555
Jan - 2015 $11159
Feb - 2015 $11799
Mar -2015 $12001
So this will work.
3- That really grey part. It would be better if you can get a reference letter on plain paper with your duties signed by your manager (affidavit)(without letter head, as your employer is not willing to provide it)+ managers visiting card/business card + explanation letter signed by you(affidavit) + rejection email from your employer or signed letter from your employer that they don't provide no such document as it is against company's policy.
Hope this helps.