[SalesForce] How to query list of roles that has access to a Account record shared via sharing rule

I think you'll have to cheat a bit on that one...

1. Make a rollup summary field on Account that would calculate count of "Financial Accounts". Use the optional filter options (on the bottom of the field wizard page where you select COUNT/SUM/MAX etc) to filter them by Status=Active.
2. This field on account should now become accessible in any kind of reporting that relies on "Relationship Group Member" - since it's a junction object you'll probably be even able to pull it on the related list of "rel group members" under "Relationship Groups".
   • If for some reason you can't - cheat by creating a formula field on the junction object that would point to the Account
   • or maybe just create a custom report type and "add fields via lookup". But I think it will work out of the box
3. That's it, should be reportable/queryable now? Apply rest of the filters you need.

Iterate over the pgp list and accumulate all the path group ids in a List and then use this as the predicate for an IN condition

List<Id> pgIds = new List<Id>{};
For (Path_Group_Permission__c pgperm : pgp)
pgIds.add(pgperm.Path_Group__r.id);

And then use the collection in the Where

where Path_c.Path_Group__c IN :pgIds

As an aside you're not filtering on Actions, so could there be Action records which don't have associated Path records?