The only compressor you will ever need.
Bonus EQ balance can give an instant ''Reggaefication'' without changing the overall character too much, and then turn it back for the next number instantly.
Nope. A cab needs several tens of watts at least for a drummer to hear anything.
Depending on what is coming from your DI you may even need another preamp to make a signal for ANOTHER AMPLIFIER that feeds your cab.
I haven't played with the VT but you are right on track.
On TB the almost famous Jimmy Miller once did a A/B listening challenge with a VT and a RedDI which is the gold standard for a tube DI. Only 75% could pick the RedDI which is only vaguely better sucess than a 50% wild guess when you consider that the audience are 'expert' qualified bassists.
I am quite fond of the DIY heavy cardboard plus duct tape creations. If you do it well enough it will work as a cab stand, maybe not a combo though. Some people use recycled coreflute plastic tenporary sign material.
Be very careful about the replacement amp getting the exact airflow as designed. There's going to be special measures to take away heat from tubes as well as the power amp. It won't be the same inside by a long shot.
Amp gimmicks that don't work:
Have you tried to read the positions of the knobs on Peavey's 'Trace Elliot' green backlit stuff in the dark? There's a reason Trace put the UV light out front of the green markings, so you could see it in the dark!
That looks like it's a jar of peanut butter branded Marmite. Whatever sells I suppose. Next there will be Marmite Honey and Marmite Raspberry Jam next to the Marmite Marmite.