Emma,
There are no benches from neighbors. You have to fly to Cyprus, Goa, Rio or New York. I did that and get benches regularly.
All, it is frustrating not to see stadiums at neighbors you know have them. BUT, I have found it pretty easy to get stadiums and if you fly to the above cities, you can gets some benches to complete your stadium. I completed three of them and was able to get my stadium collections from visiting only my own stadiums and Bloobouy1975 ( for some reason your name is always on my list). So all I have to do is visit the cities for the carnival magic collection. I'm almost done with this quest. I guess what I'm saying is that it is possible to do most of this one on your own. ( which apparently you almost have to).
For now I'm sending gifts out based on the person's level.
Good luck,everyone!
Lilly2,
That's very interesting, I also see Bloobouy1975 as my neighbor all of the time. I wish we could figure out why some particular neighbors are viewable. I went through the exact same procedure you did for this challenge. While I have finished the challenge, or at least have everything I need, I not redeeming my last items to keep the challenge running. I have a bunch of Villas, Cottages and Stadiums and I'm building up quite a few extra coins and Captain Hats continuing to collect all the items. While I'm not fitting the stadiums with benches and the like, I get coins and captain hats just collecting them. I have about 50 stadiums already in storage. You get 300 coins and 140 Experience points for each stadium. The same goes for the hats, gloves and whistles. If you haven't ended your challenge, consider my suggestion.
I Fly