Is there a way to sum fields from multiple relationships to C360 and join a report with opportunity fields?

I'm assuming the opportunities for each relationship are in different MDA tables? If so, you could create new fields in a single MDA table, then use rules to push the values from the other tables (field mappings in the actions) in to the newly created fields. Then you build your report from a single table. 

Thanks for the response! The opportunities are all under the Account Object not directly tied to a relationship.
Would you be able to provide an example?

If all the opportunities, regardless of relationship, are kept in the same object then you should be able to create a report with any of those columns and add it to the C360 layout. No need for field mappings unless I'm missing something...?

There are a few options based on how you would like to consume this information and what you would like to do with this data. 

You could create 2 widget reports, one with the sum of "Total Prize Pool" and another with the sum of "closed won opportunities" and add them to the summary section of the customer 360. 

To view these values across multiple accounts, you could create custom fields (either on SFDC Customer Info or MDA Company object) and populate them via bionic rules and then use in reporting.

You could also compare these values while building the rule and decide on the appropriate action in the rule itself. 

In the past, I have created widget reports for a list similar to what you are asking and it worked well. If you need to create a field for Total Prize Pool, I would recommend leveraging the functions in Bionic rules to sum the amounts and write them to the appropriate field you create.