In case of both acts employees' interest is not material as both are statutes.
PF act is applicable to you from day one of the formation of the org. Please obtain registration number immediately to avoid further loss of interest & damages. Also employees may not agree for their contributions of past period, you may have to deposit both, employee & employer contributions of the past. So hurry!
ESI Act is statutory provision. If your firm is under ESI implemented area, then ESI contribution is to be paid in respect of eligible employees from day one. Also employees may not agree for their contributions of past period, you may have to deposit both, employee & employer contributions of the past. So hurry!
Best way to go about is appoint consultant who will do the needful on your behalf. You can do the registration online & obtain both registration numbers. But you will need consultant to do initial work which you can take over later. There is nothing much to do except to load wages statement as you will see.