Animal Crossing Wild World…

Do you have to be connected to wifi to be able to buy turnips? I can’t find the lady that sells them. I know when she is supposed to come but she’s never there. Also, a guy is supposed to be playing music in the cafe but he’s never there either. Also, how do you catch the scorpion and tarantula? I’ve tried and tried. Is there a trick or something? One more question, how do you get cherry trees? I have peach and coconut. Thanks!