Allo,
One thing that you should keep in mind is that due to face issues, a lot of the students of the older Yangs were made to become disciples of YCF. There was a lot of pressure put on them to maintain appearances. The Yang taiji family at that time was obviously much smaller than it is today. The Wu style was still not even considered a separate branch at that time.
Not saying that Li Ya-xuan was forced to do that. But I know of others that became YCF's disciples due to this issue. So a lot of older disciples came under the YCF umbrella.
Also this division of Yang Ban-hou's style vs. YCF's style, etc. is fairly modern. In that past, it was all just Yang style.
IMO you should try to get the best info you can regardless of which Yang family member it comes from. Good info is just too valuable to pass up because of politics.
Li's book that I recommended to you is the best resource I've seen on any spear system, period. It has pics and descriptions of the moves, the two-man applications, old pics of Li doing it pics of his younger students doing it for clarification, it comes with a free poster, etc.
You just won't find any better resource. (I should be getting a commission for selling this stuff!)
For the staff, get thick whitewax wood. And be sure to soak it in vegetable oil for about a month first. Then set it out to dry. This cures the pole.