I always wondered this because I have some extra gold tools that I need to get rid of and I always wondered if they can also hold things like bubble wands, throwing beans etc
the only thing I've ever seen them use is the watering can or fishing rod (but I've never seen them pull the line back in). I've never seen them use the net, even during the bug competition, I always just see them look like they're going to catch the bug but I've never seen them swing the net, most of the time bug gets away. I doubt they'll use the beans or bubble wand, but it think it would be cute so I think i'll try sending someone a balloon and see if they hold it....they'll probably just put it in their house though :3
Villagers have their own tools. To my knowledge, anything you give them besides clothing just gets put on display in their house. It would neat if I'm wrong on that though.
They can carry shovels (their own). The jocks will tell you that construction dudes look tough so that's why they are carrying the shovel, LOL. I'm not sure they'll even put balloons on display. I don't think they display other villagers' pictures.
I have sent all of my villagers balloons and none were ever on display in their houses or carried around with them. I wanted their houses decorated with them for New Years but it didn't happen. I did send everyone a festive tree just before Christmas and they displayed them in their houses but some kept them on display until March or April. That looked a little weird.
Sadly they do not. I gave a villager a silver shovel and they still used their common shovel. I was playing on my sis' ACNL, but I'm getting it sooner.