What to look for when buying USB A/B/mini/micro to USB C adapters?
Your minimum suggestion is a good one.  USB C 3.1 can operate at the highest speed and so this is best implemented with no adaptors at all.  There are some non-standard configurations such as A to A that are used in certain circumstances even though they don’t have an ‘official’ use, but you can be sure that the one you haven’t got is the one you’ll need.