i think you need to evaluate the situation.
friend 1 - tell him that you dont like him at all and that he has a good girlfiend who really cares about him or if you want to you can say show me how you would treat me through her so that would give him more of a reason to date her other than getting you jealous.
friend 1s gf - if you told her that hes with her to make you jealous that would ruin your friendship because she might see you as competition in the sense that if you were ever like him she'd be out easily. so shed be watching how you interact with him to make sure nothing is happening. OR she just might be happy and drop him. but its what you think
friend 2 - he came too late into the game. lol. if you dont like him then you dont. no matter how much he cries he has to accept reality for what it was. and he cant blame you for not being aware. people do that all over the world. not your fault. he should be accepting enuogh to realize he doesnt have a chance.
bf - doesnt need to know because theres nothing happening. if you told the bf about friend 1 it might result in a fight or mistrust of you when youre with friend 1 if you ever are with friend 1. same thing with friend 2. unless you give him no reason to doubt you then you can say it nonchalantly "i think friend 1 likes me" i got this weird feeling from him. then your boyfriend might get protective but if hes secure then he would be cool with the fact that youre dating him and not worry about it.
theres a lot of scenarios but since you know them best you have to foresee how they would all react. my advice. do not tell the boyfriend and tell friend 1 and friend 2 that you are happy with your boyfriend and that if they make any further moves on you that will make you unhappy and if they really like you they'd care about your happiness more than they want to be with you.
i think thats about right.