I have not read the above links, so I am sure it gives much more info and probably more accurate, but just from personal experience and observation, the differences are as follows:
RN, must graduate from a 2 year AD, 3 year diploma, or 4 year BSN program and pass the national board exam. The exam is the same for any of the graduates, so technically all RN's are roughly equal. CEU's for maintaining licenses varies from state to state. Some require no further training, classes, etc., while others require varying numbers of hours. As a travel nurse I have to have licenses in several states. I have found that generally if I maintain my ACLS, PALS, TNCC, etc certifications that are required for my job, I have plenty of hours to relicense anywhere.
LPN/LVN, graduate from a 1 year technical school and must pass a national board exam. Both RN and LPN's are licensed not just "certificate" holders. In many settings RN's and LPN's do equivilent work. Many settings will not allow LPN's to give certain IV meds and drips, but others are the same as RN. There are differences in ability to "move up" the management ladder, but that too is subject to individual nurses and facilities. CEU's? I don't know but would imagine it is similar to RN's, and vary state to state.
CNA's, certified nursing assistants, take courses offered by hospitals, business colleges and tech schools
. Most courses are about 6 weeks. In most cases they can not give meds, altho now there are advanced classes and some are able to pass meds in long term care facilities. They work under the supervision of an RN or LPN and help with daily tasks such as bathing, ambulating, feeding, and many other procedures that may be done. This too varies with level of ability and facility.
There are many others in the "nursing" realm. There are nurse techs who many times are nursing students and are allowed a little more freedom than a CNA and can do other procedures, again based of facility and even individual departments. There are medical assistants who can work in offices and do a little bit of everything from drawing blood, running some in house labs, assist the physician with procedures, etc. Many doctors offices do not have nurses at all, but medical office assistants who have generally had training at tech schools. These are not to be confused with med techs who work in laboratories. I am not familiar with their level of credentialling, but know some are degree programs from universities while some are tech training.
I am sure this is not an exhaustive list but it is all my tired brain can think of at present.