All are significant mechanisms for the generation of resistance. Combinations of antibiotics make it more difficult for bacteria to survive, as they would have to acquire multiple drug resistance. Mycoplasma pneumoniae, a bacteria without a cellwall, causes pneumonia. All should be effective. All of these drugs are only effective against bacteria with cell walls, as they target cell wall biosynthesis.
Clavulanic acid is a potent inactivator of beta-lactamases.
All of the above have similar activies. Tazobactam also inhibits beta-lactamases. They are not readily absorbed into eukaryotic cells. Bacteria possess porins that allow access of penicillins to the target enzymes. Eukaryotic organisms do not possess porins.