Attention Seeking 5 Year Old

So some back story, my step daughter was removed from her mom's care end of 2016 and has lived with us since. Mom was in jail and prison, we did calls and video chats and letters until it began making things worse. She's had a very rough begining. However, I am struggling with parenting her. I don't want bashed, but I struggle so badly. I remind myself of what she went through with beung neglected, I try to tell myself it's all okay a phase it'll get better. She's 5 though, she is overly friendly to people, we can't have adult friends over because she finds and makes any and every excuse to sit with them and be up their butt. My youngests is in a early headstart program and if my 5 year old is home she finds any and every excuse to come downstairs and take the attention away from my youngest. We've had a lot of lying issues from her, especially when we moved last year she began telling her teachers at school we left her alone and nobody fed her, which prompted in a home visit and them asking me if we had enough food and was she getting fed because she was eating double the food at school and had told them several times we just never fed her. At that time we had food stamps and house was filled. Again this year she told her teachers nobody fed her and they enrolled us in the backpack program and don't believe us when we told them we have plenty of food. My pantry is stocked, we just moved to our new place in December. Between the lying and constantly seeking attention I'm getting really really irritated with her. If it's not that she's taking things from kids at school stating they gave her the money, or gave her a bracelet etc. I've been enforcing space and boundaries, but it's not registering. She talks to strangers, invites our adult friends to spend the night or tells them they're going to take her and let her spend the night at their place. Her dad yesterday went next door to the neighbors we live in a duplex. She threw a tantrum because I told her no she wasn't going next door. She also poked his son in the eye yesterday. I volunteered at her school and she is always hugging people even when they make it clear they don't want hugged. As far as the mom situation, mom and her family haven't been steady since prison release so we've cut off communication with them as it makes her super upset when phone calls end and makes her regress from any progress with night time potty use. Last week she had my phone and her aunt who she doesn't remember at all, messaged me and she thought it was my friend however took it upon herself to video call and since then her nightmares have come back, she was sleeping through the night no nightmares. Her dad called a place this morning trying to set up some counseling, but until then what can I do? I feel like giving her more attention than her brother and sister isn't fair, and I don't feel it's fair she gets rewarded for not listening and acting out. I've been spending more time with her too but again doesn't change her acting out. Help me out guys. I feel we but heads 24/7 it's always a power struggle. I don't know what else to do that I haven't been doing or done already. I even got books to read regarding the absent mom thing and different families because she's always saying she wants to live with her mom because we are mean. Her heart also got broken when her mom sent her birthday stuff and had her new step daughter sign the card, my child's heart shattered she feels replaced now. Sorry for being so long I just really don't know what else to do for her. :(