Yes there is 15% seat reservation at esic colleges for students applying via all india quota allotment. pls go through the counselling scheme in the website mcc.nic.in( as per updated information)

But I am not sure about obc reservation for all India quota students.

No, you can't add the ESIC colleges. As per the criteria under ESI sheme candidate should have the valid ESIC certificate.

ESIC will be provide the ‘Insured Person’s Quota’ to those who have successfully met the eligibility criteria under the  ESI Scheme and have qualified in NEET 2020. The counselling process will be conducted by Medical Counselling Committee (MCC) that will be based on the merit-cum preference of college and reservation status.