Well, the idea behind a vented hood is so you can dump the heat from the bulb somewhere else, like outside. If you have to exhaust into the grow area, you might as well take the lens out of the hood and let the rest of the photons through. (Be careful about the bulb, then--no splashes). Depends on whether heat helps or hinders you.

The filter will work fine like that. The closer to the floor the more kicked-up debris is going to foul your prefilter, though. Most folks prefer to suck through the light rather than push through it for a couple reasons. If you were venting to outside, you could go filter> light > fan > outside and do it all with one hole. Make sure the hood and ducting are airtight or you'll suck smells in after the filter.

And keep those ducts as short as possible. And minimize bends, particularly sharp turns. Solid ducting's got a lot less drag than that dryer-hosey stuff.

Gotta go, HTH.
Hermie