Your first post, middle picture is as it seems: Ft. Leavenworth. The actual crest that is worn as a uniform item is the shield with 3 oil lamps. 4th is the 29th Infantry Regiment.
Your second post is the 4th Infantry Regiment and USARSO crest. US Army South. I remember that being one of the last assignments a friend took before ending his service. He like Ft. Buchanan, of course, he was born just up the road and grew up there.
As for the others, I'm unsure.
Did you try the Institute of Heraldry?
http://www.tioh.hqda.pentagon.mil/
http://www.tioh.hqda.pentagon.mil/DUI_SSI_COA_page.htm
Hope this helps you find other worthy homes for these.
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