The Good!! The Bad!! And The Ugly!!!!!

Looks like a good starting point---not uncommon for a S/W car. I'm thinking you could find replacement stock tubs, slit them & mini-tub it, if that's what you want, & it would alleviate some of the headaches squaring away what you got. Never heard of "Dutchman" axles, but if you're not looking at building a killer engine, I wouldn't worry about it. The floorpan issue can be cured with replacement pieces if necessary. The one thing I would do (& it's a quirk of mine) is add frame connectors to the car no matter what your plans are with it. How you install them is up to you, but IMO, dealing with 40+ year old cars & todays technology in engine building means you're producing more HP than the engineers back then ever dreamed of, so why build a car that'll shake itself loose right from the start?
It looks like a great alot of fun, enjoy!