What are the two most efficient ways for a Salesforce Admin to accomplish this task?

What are the two most efficient ways for a Salesforce Admin to accomplish this task? Universal Containers is launching a Community to drive their channel sales. The requirements are as follows:• Integration with a Back-Office Legacy System that supports API-Level Integration and Salesforce Connect. This integration does not exist today.• Integration with a pricing and quoting tool. This integration exists today for internal users in the Salesforce org.• External partner users must be able to configure the quote using the pricing and quoting tool from the Community.• The pricing and quoting tool must support Community users.• Universal Containers owns licenses for Salesforce Connect.