Vanguard VEO 265AB Aluminum Tripod with TBH-50 Ball Head

I have not tried it. I have done some video on the tripod with my Nikon 7200 (not with the FF D810). I don't see why not, but I would ask the experts AT B&H. They are very reliable. The tripod is very good and very light for my needs which is mostly still photography.

The height without the center column extended is about 45 inches.

The Maximum Working Height of 59" / 149.9 cm includes the head.

The quick release plate is aluminum.

Yes it does. This is a great tripod especially for the money. The only draw back is that there is a small knob to adjust ball tension which makes it difficult when using a long heavy lens.

For my Mamiya RZ67 kit, I use a much sturdier tripod and a choice of heavy-duty Manfrotto heads with long or short handles and their large hexagonal quick-release plates, leaving one plate attached to the bottom of each body for convenience. Although I love my Arca-Swiss ballhead and carbon fiber tripod and use them extensively with pro-sized digital bodies fitted with RRS L-plates, I usually won't use them for the RZ except under circumstances where a heavier tripod might be impractical (e.g., indoors on location where there are restrictions). In any event, I would prefer not to use a compact 3.7 pound tripod and ballhead to hold a 9 pound RZ or RB67 kit; however, one could use it cautiously until being able to afford something sturdier. It is wonderful that people are still shooting 2-1/4 x 2-3/4" medium format, and you will love the tonal range and ineffable "there-ness" that only film can provide!

As I am the owner of this tripod, I will answer the detail info on this. As you know the tripod can be stored by extend the middle pole to the top then it will fold forward where the head will position upside down. When its upside down it will not go up to position the upside down head to be up or down. Only thing you can do is to flip up to be positioned as normal position like other tripod (just as photo shows).With the normal position you can adjust the height and using the ball head you can position the camera downwards. If you are looking to position the middle pole to be horizontal like Monfrot tripod, you can NOT position that way. It only goes up position then up and down with ball head, or flipped down position but not going up nor down.

Yes.