What is the actual process fraternities do to decide to give out a bid?

[madoug]

I would also add that, in general, a small handful (or in some cases 1) of actives can prevent a bid from being extended.

and unfortunately, this may have nothing to do with you, but rather their attitude about who it is that does want you to get a bid. Brothers (and sisters) do not always play well together. So if you do not get a bid from your "First" choice consider yourself lucky and that your attention can be directed elsewhere.