MPPT is expensive and to get the most out of it you really should full build the system in one swoop. PWM controller with 12v panels is much easier to get an oversize controller and add panels as time and money permit. MPPT is more to use the larger 220+ watt 24 volt panels to charge the 12v battery.
Plain voltmeter or controller remote monitor is fine for keeping an eye on things. I would sooner have more battery over an independent battery monitor. Although lots of people love their battery monitors.
I hope that smart charge converter is not a 55+ amp WFCO.