You can, and in most cases definitely should, hire club staff. Their wages are depending on their reputation and length of the contract offered to them - longer contract equals higher wages. In case you decide to terminate their contract, just like your players, they will be compensated for the loss of the wages from remainder of their contract.
Reputation of your future employee is not directly linked to his skills - if you choose to hire coach that is young and inexperienced it does not mean that his skills are lower than the one that used to be national player, it is only more likely. Also in Pro game modes you can send your employees to a course that would help them improve their skills.
Due to our basic rule of uncertainty staff skills are not defined by any visible parameters, but there are things that may suggest their skill levels. For example better scout could provide you with more or better informations about your opponents. In same way you are not given any info if your staff member that went to a course actually improved his skills.
Why does it work that way in SMFC Online? Actually it is partly based on business theory of incompetence - for example if you go to the doctor and he treats your illness you assume that he is competent. You can only discover that he isn't by going to different doctor and finding out that actually there is a better or safer way to treat your illness. But in that theory the first doctor will still be sure he is fully competent, because no one yet proved him wrong. Same rules apply to your staff - they provide you with the best support they can give, but you can't be sure how competent they actually are until you find your new staff member to be better than the old one was.
Right now there are 6 club staff positions to be filled: