Will these work in 2015/2016 Ford Flex?
Yes it will work on any car with fuse box,All you do is remove the fuse in the socket insert this add a circuit fuse and insert the original fuse. Then your good to go.
Follow the colors to match?
Red, blue and yellow indicate different gauge size of electrical connectors for easy identification when using.
Which crimp tool works best with these?
Most of the time, You can use a ratcheting crimping tool that comes with a variety of crimps and sizes. It works great.
How do you attach these to wire?
You will strip the insulation back from the end a ways, slip the connector on and crimp it. With these "spade" connectors, you are making a quick disconnect, instead of a solid connection using a "butt" splice.