Not quite sure what you are asking. If all three monitors have those three ports, then you could connect one via DVI, one via HDMI, and convert a displayport to either HDMI or DVI to avoid analog altogether.
Yes, VGA has a maximum resolution limit dependent on the RAMDAC of the adapter. Generally though, even cheap commodity RAMDACs will be able to drive up to at least WUXGA 1920×1200. However being analog, the image quality is highly dependent on the quality of the output components. The problem is that a cheap active adapter designed to sell for $15 tends to be made of much worse quality parts than a graphics card originally intended to sell for hundreds. So often the image starts to get blurry over 768p or so, especially if...