The only odd part I see is the last one, where the engine RPMs went way high. That can only be caused by opening the throttle. To run faster, and engine must have more air/fuel mixture. And since this is not a Toyota, and actually has mechanical throttle cables connecting the throttle to the carb, either the throttle got moved, the cables are binding, or they are routed incorrectly, and opened the throttle when you turned the handlebars. Since it is mechanical, the cause of that problem should be easy to track down.
Even in AZ, in the summer, in the shade, my Vulcan takes full choke to start, and needs at least partial choke to run for the first couple of minutes (it is actually an enrichener circuit, not a true choke, and works in a completely different way, but I don't believe that is relevant here)
The stalling could very well be caused by a partially plugged pilot jet. That could also be the reason it needs more choke than you seem to feel is necessary. Before removing and dissassembling the carbs for a thorough cleaning, there are a couple of things you can try. First of all, if the carbs still have the EPA plugs in them, covering the pilot screws, you need to remove them, then remove the screws and springs, spray some carb cleaner back in there where the screws go, put them back in, lightly seat them, then back them out 2 1/2-3 turns. Do this even if the plugs have already been removed.
Now remove the fuel lines from the petcock, and drain the flat bowls on the carbs (make sure what kind of drain screw you have, mine has Allen screws, apparently some had straight slotted screws) You loosen the drain screws and the gas will drain out. Now close the drain screws, and using a very small funnel, fill the carbs with Seafoam through the fuel lines, let it soak for at least 24 hours, and drain it out. Put the fuel lines back on, close the drains, and restart the bike. It will take a little longer than usual, because the carbs will have to fill back up with gas. Now run a couple of 16 oz cans of Seafoam through the tank, one full can per full tank. If that doesn't help, you are probably looking at pulling the carbs to clean them.
The tach shows actual engine rpms, and readings will vary considerably. It is probably just reacting to different engine speeds if the engine is not running consistently. If there is a problem with it, it is totally unrelated to your other issues.
I am a motorcyclist, NOT a biker.
1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike