Question on how to set up

I am taking a already configured CB + CBSubs and taking it over, my problem is I think the people I took it over from did a crappy job at setup making it a real mess to work with.
If someone could tell me what you would do I'd appreciate it.

The website has 4 plans and each plan has a paid newsletter by post and a free email newsletter you can sign up to. Right now they have the Newsletter by POst set as parent plans under each MAIN plan.
1. Is this correct to do? My question comes from when I trying to build a Fabrik list, as the old site had before. The customers come up as duplicates because the CBSUBs subscriptions table reads all the plans including the parent plan, there isnt a separate table for them and the ParentPln-id and Parent-Plan table dont actually show the PARENT PLANS, I cannot figure out how the match up. The P-Plan id's are 7,5,9 and in the database I only have 0,1,2. And the parent subscription table shows a year or a 4 digit number instead.

The biggest problem I am having is in Fabrik the old website had a list that showed Both the Subscription and Newsletter separate and cannot figure out how to do this as technically there not.

Any ideas?

Right now they have the Newsletter by POst set as parent plans under each MAIN plan.

I don't understand. You can't have a parent of a parent. You mean they have each newsletter as a child plan of your parent plan? Something like the following?

Main Plan
- Newsletter Plan
- Newsletter Plan
- Newsletter Plan

1. Is this correct to do?

I don't see anything wrong with it. If the newsletters are free it's probably better to just use AcyMailing and its CB plugin so they can subscribe to newsletters using a tab/field instead of making CBSubs do it.

My question comes from when I trying to build a Fabrik list, as the old site had before. The customers come up as duplicates because the CBSUBs subscriptions table reads all the plans including the parent plan

Nothing to do with the usage or CBSubs table structure (which is correct and efficient) and everything to do with your query not being specific enough. The parent plan id is stored in the "parent_plan" column of _cbsubs_subscriptions. So anything with a "0" for "parent_plan" has no parent. To match "parent_plan" to its subscription row you'd just check against "plan_id" in your query.