Welcome aboard Michael!
Good choice on machines. You will fall in love with the capabilities of that machine and the implements. I bought a like-new "scratch & dent special" that came with three implements. Two of which I never use.
When you buy new, the dealers offer you smoking deals on implements. That is the time to get what you need. On a few items:
Backhoe- Plus: Super handy and very useful for trenching and general high lifting and placing of objects. Neg: They raise your CG significantly so the machine gets a little tippy on hills. They don't clip on and off. It takes time to get them on and off and while they're are on, your 3-pt hitch is out of action. When they are off, they are not easy to move. If you leave them out in the weather, they won't last near as long as a dry location like a barn. You get any rain up there?
Box scraper- An absolute must. Plus, they are cheap. Get one as wide as your machine. Basic grading and road building tool that will get you 90% of the way there (with practice!). It can drag a pile along as well as push a pile, in reverse, where you need it.
Land Plane- Kind of like a box scraper but it only works in one direction and it fills in dips and variations far better than a box can. Great for routine maintenance of a gravel or dirt road. Keeps it leveled out far better and easier than a box scraper. One tool you will be really glad to have if your roads get a lot of travel or precipitation erosion.
Brush Hog- Mega-monster mower for turning weeds and small trees into bio-mass. What's not to like?
I would tend to get the bucket that is wider than your machine. My bucket is 72" and when I go backwards and let the bucket "float" it covers my tracks nicely. Handy when trying to fine tune a pad or road. I am thinking with the bigger machine, you'll prolly want the big one. The 5800 should have lift capacity to lift wet soil in the 84". Again, when taking it off to put on the forks, it'll be heavy to move by hand, but you can pick it up with the forks and put it out of the way.
Forks- I was dumb. I bought clip-on forks (clip on the lower bucket lip) and they cut my lift capacity by 50%. You will really get a load of use out of those so get a set that mount on your bucket quick-mount without reservation. Money well spent.
Suggestion: Get your rear tires filled for extra weight.
Have fun. Learn how to upgrade pictures. We love to follow your work via tractor "porn."