1) If I, as the main applicant apply to renew my visa with my new employer's CoS through a PEO, would this affect anything about the visas of my dependents?
I have found out in the application form that, if they apply with my, we do not need to show proof of maintenance (i.e., 600 GBP per person), however, we would need to prove that we have had 600 GBP per person for the last 90 days, if they apply later.
2) Are there any risks if my dependents make their application by post after I receive my BRP from the PEO?
Still dunno. The gurus of the forum might help
3) If all three of us make a postal application, what is the max. date that my current employer is allowed to have me continue working: My current CoS is due 21/07 but they may be positive to extending my contract. If the postal application extends beyond 04/08, would they be allowed to employ me after this date as if in an extension application with the same employer situation?
dunno. The gurus of the forum might help.