Just from my own knowledge of the area, yes, the examiners are familiar with the local CFI's. However, this doesn't necessarily give the advantage. To have a DPE's confidence requires a CFI to send a succession of students that are at an acceptable level of proficiency. The DPE does want you to pass, but also is keenly aware that they are signing their name on a line that holds them responsible for your actions as a licensed pilot. That's a pretty big responsibility. From the conversations I have had so far, the DPE is assessing you on multiple levels. If you can demonstrate safety, and ability to adhere to regulations and so be it, to know precisely the questions he is asking-they don't expect you to know everything. But do expect you to know a lot. If you feel comfortable in your knowledge then don't sell yourself short because you thought the check-ride was easier on you. He still is taking the responsibility and signing his name.
As far as airplane make and model, no, I think for the most part, it really doesn't (or shouldn't) make a difference. Every examiner has preferences though, and it is helpful to get briefed before hand as you experienced
Thanks for the thoughts, I will be sure to ask.