I am an LPN and do IV push meds, blood transfusions, start IV's, draw blood, do assessments, etc, etc, etc...about the only things I can not do at my hospital is charge, and push a few cardiac meds. Check and make sure that LPN is not allowed by state law to do the things she's doing. And if it is not in her scope of practice, then yes she is doing something wrong. I would talk to her about it and if it continues, report it to your manager. (I know what you mean by this though, we have a CNA/tech who starts IV's all the time, even though it is definitely not in her scope of practice...we are all just waiting for her to 'get caught' by management and get fired, since we have all talked to her and the manager about it and it still goes on.)
As for the tech/CNA not turning the patient, yes the RN is just as responsible for the patient being turned! A lot of RN's and LPN's do not feel like it is 'their job' to do the actual turning, but they are responsible to see that it gets done at least q2h, whether by delegating it to someone else or doing it themselves. So, yes the RN and/or LPN is ultimately responsible for that patient being turned.
Being a new nurse, you will encounter some people doing stuff wrong, or taking shortcuts, or simply not caring...by doing the right thing yourself, you can help set a good example for others. Or, if that doesn't do it, at least you can go home and sleep at night with a clear consience.
Hope this helps!
P.S....About your post above, lying about vitals!!! that is horrible! A nurse here in Indiana (RN) recently lost her license FOREVER for that! She is skating on some very thin ice!