3.3v and 5v, oh my!

The MCP1825S-330 can handle only 6V input. The me6211 can do 6.5V and the rt9013 5.5V - so better not power those with more than USB power. Low drop-out indeed, that's their plus.

The AMS1117 is rated for minimum 1.5V drop - but on the other hand can handle a 12V supply.