Made my own bracket from flat stock to go where it fit best, a few barb connectors, some hose, couple of shutoff valves to isolate the filter, good to go. Now I just raise the bonnet and both filters are in easy reach.
Seems that even with a bad battery you should get some power to the dash, etc. If you have an electrical diagram start at the battery and trace to a point where there is no power.
As far as bad batteries...
I've had batteries that were on maintainers/chargers overnight and read 12.6 volts not...
Baby steps.
If you're shearing bolts one after another they may be grade 2. Step up to grade 5 and see if it reduces the problem. Grade 8 may damage other parts before shearing but you can try them if Grade 5's don't work.
Shear bolts are cheaper than tines, gears, PTO parts, etc. Once you get a plot tilled and de-rocked you should not have an issue.
There are some walking around with less common sense than others (current company excluded). There are always those who will do things that a piece of equipment is...
There are many tools out there to relieve pressure on the hydraulic hoses to help connecting them. Here is an example but search to find the type of connections on your tractor. As far as a tool to actually help connecting them physically after the pressure is reduced I have no idea.
Pressure...
You can find an electrical diagram the your B2650 in the WSM here.
Looks like you have a few options as well as connecting direct to the battery (what I did because I'm lazy).
1 - tap into the electrical outlets (front and rear)
2 - tap the relay circuit
3 - tap into the front and rear switches
I went to the Kubota website and clicked on "Build My Kubota" for the LX2620.
The models that came up were LX2950 and B2779 as options. You'll also need the 4 point hitch and subframe LX2940B if you don't already have it. Not sure if that kit also incudes the mid PTO shaft.
Over $8K total...