I am still waiting for my OPT to process and do not expect that my EAD card will arrive until in about 6 weeks. It is my impression that there is no guarantee for the EAD to arrive from USCIS. However my employer is pressuring me to provide a fixed start date so we can sign a contract. Can I provide such a date? i.e can USCIS guarantee that I can begin work at a certain predefined date (through EAD or interim EAD for example). Does the interim EAD still exist?
First of all kudos to you on finding the job before applying for OPT. Most students always do vice versa and end up in not such a good situation. Since the regulations state
You may apply for OPT up to 90 days before your final semester ends,
I would just take the worst case scenario and give the 90th date. By the way the obvious red flag there is the contract part. I would thoroughly check on what the contract is about. Remember contracts in US vs what some are signed in the other countries are different. So read closely anything before you sign. Also you can ask to include the clause there that this is pending receipt of OPT as issued by USCIS.