I love the 3-way set up, If you have the means, get them.
The 6.5 woofer, are you talking about in the rear speaker location? If so I do not think that you will have the mounting depth for that magnet. My 6x9's didn't set right on the plastic enclosure. I ended up using non-hardening modeling clay to seal up the void.
Can bee seen
here
I would hold off on subs, or consider
these, You will not get teeth jarring bass from them, but you also only need 180W RMS (I know they are only 90W, but you want the headroom) so you will not need a huge amp to push them.
If that isn't enough bass then I can recommend a little more that would go the the extreme rear corners of the hatch.