You might try sleeping with her in her own bed, if that is possible physically, and weening her on her own. It may take awhile. But it might work. Also, a night light or a table lamp as a night light might help also. Leave it on for both of you. I might suggest a pal to sleep with, like a teddy bear, big enough to wrap her arms around. Her security has to be transfered to something else.
If you both can't fit in her bed, then you might consider a wider bed for her to fit both of you. But she has to end up alone in her bed. I can't say how long it would take. But if you give up, the next best thing is therapy. Yes, I am afraid you made a mistake by keeping her in your bed. But don't be concerned with that now. Her well being is and your sanity is important.
Reading your post it would seem you have some concerns on safety and have passed this on to her, perhaps some over-protectiveness,, hence the hidden doorbell, and allowing a phone hidden under a chair, she has picked this up, most children copy us so you will have to make her feel safe again,if you have concerns ,she will have them, it is a learned behavior.,is it also possible she has hidden when anyone comes to the door from some fear you unknowingly have expressed.So you have to undo all of this,from now on let her behave hiding when anyone comes to the door , dont feed into it, no words , or the sleeping tell her she has her own bed and her own room, read her stories and leave a hall light on if she wants you to, tuck her in and walk away, she will come out she will yell , take her back , be consistant ,it will take a few nights but she will get it. really she has to unlearn how you have shown her to be, I think less words are better simply make sure she feels safe by Your attitude. Good luck