And Leo the bartender ask him to join tooYou need 3 people to go to Freds gym. Talk to Valerie and she sends her boyfriend, talk to Barbara and she'll go, the 3rd person is Margie(the chick that works at the sports center but you will need 5-7 friend points for her to agree to join and to get those, find her at the coffee shop/in the tennis courts and hang out with her(I think shes at the courts on Wednesday when Ruby is working but I'm not 100% sure).
And Barbara's quest is bugged, you don't have to buy multiple strap-ons/dildos. I was stupid and wasted money on multiple of both but I finished her quests lines and it still says I have to talk to her about my own studio.