The 3rd condition as follows is what keeps it from applying to renewals.

3: [var7] Equal To N

The below ensures it only applies to new subscriptions. If you want it to apply to new subscriptions and upgrades you need the below.

3: [var7] Not Equal To R

That ensure it applies to new subscriptions and upgrades, but now renewals. [var7] will be one of the following.

N = new subscription
R = renewal
U = update

The following conditions are all that's necessary for acting on new subscriptions to a plan.

1. [var3] Equal To PLAN_ID
2. [var2] Equal To A
3. [var7] Equal To N

If you want it to cover all purchases except renewals you'd use the below condition for var7.

3. [var7] Not Equal To R

Beyond that I don't know what to tell you. These are the exact conditions several integrations are using. Review CBSubs Emails code for more examples as it conditions against a wide range of states.

Depends on how you're purchasing. Are you using single payments only? Each single payment generates a new basket instead of renewing an existing in which case yes it'll always be a new purchase. You can likely just add another condition to check if the field has already been changed. Your alternative is you'll need to condition off the subscription object in [var9], which gives access to all the data stored in _cbsubs_subscriptions for that subscription row.