It would run more smoothly if there were fewer people in the communication chain HOWEVER do not connect your client direct to the developers.
1) clients will casually "remember" things that need to be added and go direct to the developers with their requests, which will cut into your margins
2) developers that you don't have air-tight contracts with will negotiate direct with the client and cut you out - make no mistake about it, you could have a great relationship with the client but business is business

Do NOT mention the development partner name anywhere. The client is not signing an agreement with, or contracting with them - it is with YOU so the agreement needs to be with you.

Unless you are planning to reverse the relationship and become an affiliate of the development company, you need to touch all the money. Why would you allow your valuable clients (assets) to be managed in any way by someone that isn't your company?