I'd spend some time going through the archives here and CTB. There are a few discussions on hooking up 3ph implements. More important, I'd read everything I could about operation and especially safety.
I don't think there's a 3ph implement that can't be attached by a single person. However, like most things, there are a few tricks to learn. You can start off learning the tricks here before you start exposing an uneducated body to the hazards of a tractor. Putting implements on and off a tractor is a breeze, more or less. The greater problem is getting implements in and out of trailers and truck beds.
The hardest implements to attach are posthole augers and pallet forks. They both fold flat and have to be hoisted up and supported to make the top link pin. My pallet forks are too heavy for me to hoist and support alone. However, I attach it alone using a cable come-along, clevis pins and transport chain with grab hooks. You'll learn about these things, and 5' wrecking bars for shifting implements around.
A 3ph tractor is one of the most flexible things known to man--outside of politicians. Almost any type of equipment is available in a 3ph version. Outside of the loader, the most common implements are rotary cutters and box scrapers or blades. These items tend to be used regularly. Agriculturally oriented implements tend to be used for one or two periods a year and are tough to justify unless a lot of land is worked. Of course, some implements have multiple uses. Loaders can be fitted with forks and a range of other attachments. The rear blade on a box scraper can be used as a poor man's dozer. The scraifiers on a scraper make a poor man's tiller. And, of course any blade makes a decent snow plow.
A tractor tends to become specialized by the nature of the work that has to be done and the budget available to buy more toys. I have quite a bit of construction and material handling to do in a snow area. I have a snow blower, backhoe, box scraper, and 3ph pallet forks. If we didn't want to leave out bush as bush, I'd have a rotary cutter. If we worked more land than a garden, we'd have a tiller. But yikes, a rarity among tractor owners, MY WIFE ACTUALLY WANTS ME TO BUY A
CHIPPER/SHREDDER. We do have brush piles to manage.