You know what you need to do. Why do you need us to bless it? Take responsibility for your life and home. You're not going to "avoid conflict" with these people, so either you go or they go, or you learn to ignore them, or at least tell them to fuck off and mind their own business. "I care for her" is not an excuse not to take care of yourself.
The protocol is for you to give them their 90 day move out notice as soon as you are legally allowed. I am surprised you've allowed this to go on for so long. It will be hard at first but once they're gone you will be so glad you did it.
Continue to annoy the shit out of them as you've been doing, until they man up and move out of your home. Then, get the new girlfriend to chip in on the rent.
2nd - supporting them, really? it seems like you may have some poor boundary skills, maybe you should work on that.
3rd - move out or ask them to move out, but you already know that. So what is stopping you?