Default Enrollment and Automatic Enrollment

We have 2 Benefit Plans.

1. Medical Plan with 3 options, each option for different set of employees, options align with their positions. customer wants all 3 options to default as per their eligibility which seems possible and working too.
2. Another medical plan with 3 options, each option for different set of employees, options align with their positions. customer wants all 3 options to Automatic Enrollment as per their eligibility?. is it possible?

is there any problem if we Default or Automatic 3 options in a single plan?

will there be any issue in future for maintenance?

Thank you!