Solid Hardwood, Engineered and Laminate Flooring - Laminate - install questions

We are planning on installing laminate flooring in our living room and have few questions. :confused:

First - we have a new front door going in within the next few weeks. Should we install the floor first or wait until after the door installation is complete?

Second, there are metal hot air vents on the wall/floor that jut out into the room beyond the moulding, angled toward the ceiling, not sure how else to explain it... Question is how do we trim out these vents to hide the expansion gap?

Edit: I forgot the last question! Everything i've read says to install the flooring parallel to the strongest light source to avoid showing all the seams. I've also read that if installing over existing hardwood floors (in this case old stained pine), that we should install in the opposite direction of the wood flooring.. In our case these are conflicting directions....which would go with? I should point out that the light source in this case is a large 10 ft. wide window that faces north and gets no direct sun..

Thanks for any advice..

Beth