Yes, and yes!
Source: I got the badges before that way
This does not work with island tours though. :/
For the planting one go on the diving tours for all the palm and fruit trees. Think I got 9 baskets of fruit each time I went.
All my extra players got their gardening badge using the island.
The fastest way to get the bug amount caught badge is to go during the afternoon. I replanted 4 trees in the middle and placed about 10 flowers on the grass. Caught 100 in a short period of time and got a bonus sun tan. Sold all the low price bugs to the little girl.
For the fishing amount I found it easier just fishing in the ocean in my town. The golden or silver fishing rod makes fishing easier.
Thanks, I didn't think it would. It's more so I can plant a ton of trees and cut them down and them plant them again (to cut them down AGAIN etc. )
You don't even need to let them grow honestly. It counts just planting them. What I did to get gold was grab all the fruits I could gather from palm trees and tours, stand on one spot and plant, dig up, plant, dig up repetitively. 100% works. first gold badge I achieved! ^^