The Opinyin plan for Freshdesk Integration is sold on a per-agent basis to align it with the way Freshdesk is purchased and to make it easy to relate to the way people work with Freshdesk. However, there is no direct link between the number of Agents you purchase in Opinyin and the number of Agents you have in Freshdesk. This was the best way of aligning our policy of customers paying only for responses and keeping it flexible for Freshdesk users who may have agents that don't handle a lot of tickets.
Each agent you purchase in Opinyin has an allowance of 100 responses per month. The number of responses you need is very dependent on how many tickets you close or resolve per month in Freshdesk. If you assumed you closed 200 tickets per month across all your Freshdesk Agents and you had a response rate of 50%, then 1 Opinyin Freshdesk Integration Agent would cover all your Agents in Freshdesk.
So in summary, yes, you can share the aggregate response allowance of all the Agents you purchase in your Opinyin Freshdesk Integration plan across all the Agents you have in Freshdesk.