We have an app built for both Classic and Lightning UIs and we need to roll out it to the customers as one package.

We do not want to force customer to set up the My Domain in each Orgs where they install the app as managed package includes lightning custom component.

1. Is it possible to have one package to support both Classic and Lightning modes without requiring My Domain?
2. What are people doing on the AppExchange where they have only one package, but they would like to support end-users who may or may not have My Domain active?

Question referenced from https://developer.salesforce.com/forums/?id=9060G000000IAPPQA4 but I have similar use case.

We have an app built for both Classic and Lightning UIs and we need to roll out it to the customers as one package.

We do not want to force customer to set up the My Domain in each Orgs where they install the app as managed package includes lightning custom component.

1. Is it possible to have one package to support both Classic and Lightning modes without requiring My Domain?
2. What are people doing on the AppExchange where they have only one package, but they would like to support end-users who may or may not have My Domain active?

EDIT: 3. If we enable My Domain in our packaging org, will it impact our existing package or create any dependency?

Question referenced from https://developer.salesforce.com/forums/?id=9060G000000IAPPQA4 but I have similar use case.