Hi petiteviolon,
Yes you have roughly described the workings of micro-inverters and Solaredge optimisers.
Micro-inverters are fitted to every panel and are the best options for rooftops with multiple aspects and small/difficult mounting locations. As you mentioned a big advantage is that if one micro stops working it does not effect the other panels. Yes you can have only 1 or 2 panels with micro inverters if you like.
SolarEdge power optimisers are very different and work together to deliver the optimum voltage (380V) to the SolarEdge inverter. Generally this works very well but you need a minimum of 7 or 8 (unshaded) panels to reach this required voltage.
What type of rooftop do you have? Is space and shading a problem?