Sorry to leave you hanging for so long. I've only played second edition, but I own the first edition rulebook. In first edition, there are no wait tests for a model to intercept an attacker charging at his buddy in his unit. In second edition, you need to make a test to do that. It is better odds to save your wait marker for when you need it yourself and can use it freely, for the most part, but there are times where you want to press ahead and go for it.
I'll re-read your posts and see if I can answer more of your questions, as I have time.
Summer is slow around here.