You are fortunate to ask this question onn this site because IrishStat has been automating ARIMA models for over 30 years (sorry to give away your age Dave). Also Rob Hyndman wrote the auto.arima procedure in R. I have a connection as I took my first time series course in a short course by Box and Tiao at Carnegie - Mellon University in 1974 (giving away my age now). Also when I was the Chief of Statistical Research at Risk Data Corporation (in the early 1990s) I hired Terry Woodfield who authored the ETS software at the SAS Institute just before we were able to draw him away. I am sure PROC ARIMA has gone through many changes but i am sure that if you make contact with Terry he could probably help you.
Personally the way I learned it from Box, Tiao and Pack ARIMA modeling is an iterative process that should be gone through manually in stages with the user making decisions at various stages. That is not to say that good results cannot be obtained by automated procedures. In fact I think that Dave Reilly (IrishStat) along with his son Tom have so much experience doing this that they will contend that they could produce a better model with their algorithm than I can do manually and they may be right. But my point is that for a time series specialist to take that approach takes away some of the steps that help him really get to understand the characteristics of thee seris very well.
One thing that always troubled me in the early years was that the Box-Jenkins methodology was revered a little too much. Estimation is by conditional least squares and so the normality of the residuals is important and often overlooked (a buried secret). In the late 1970s i work on the problem of outliers in time series and Darryl Downing and I published a paper on the topic in JASA in 1982.
Since then other like Doug Martin, George Tiao and Ruey Tsay have made much bigger contributions. IrishStat is aware of that literature and has incorporated their ideas in his software. That is why he emphasizes checking for level shifts and outliers before fixating on an ARIMA model. That aspect of his software makes it somewhat unique. It is different from auto.arima and SAS/ETS. So keep that in mind in your search for other automated procedures using SAS.
I hope you appreciate this as an answer even though it does not directly answer questions 1 or 2. I am sure you can find Terry Woodfield on the internet or go directly to the SAS Institute with your questions which are very specific to SAS and really require someone with intimate knowledge of the SAS algorithms. I don't think you will find anyone on this site who could give you better help.