I recommend having the below setup.

Plan 1 (Free, Lifetime, Exclusive)
Plan 2 ($$, ??, Exclusive, Allow Upgrades)

Plan 2 would be your paid plan and plan 1 would be you free plan. You'd then use CBSubs Field Tabs Protection to protect profile tabs/fields based off their subscription to Plan 2 (this would mean subscribing to Plan 2 gives more features for example).

Everyone should be able to view the 'member tabs' (or the member has the option to allow public viewing or not).

You could simply not protect the tab. If you want users to control privacy you could install CB Privacy and enable privacy controls for that field.

I would probably want to enable "Create Subscriptions also for free lifetime plans".

With the above example this will be necessary.

I highly recommend reviewing the CBSubs documentation as it will guide you through your CBSubs installation and configuration. It also includes many helpful usecases to give ideas on what CBSubs can do for you.