Exhibit A: "While my wife did say I could do whatever with the basement."
I've been in many 6'9"- 7'5" high basement, and I have a 7"1" high basement, so I don't see three rows working.
I'd suggest some graph paper and a side view sightline diagram, and you'll start to see three rows isn't a good fit for 6' 8" of height.
And even if it did squeeze in vertically, the projector throw and where the projector lands, is another possible headache.
And you don't need a 19" riser..... You could offset the seating with that small 100" wide screen, and likely get by with a 5-7" high riser,
when the seating doesn't recline.
Bean bag chairs would my go to, overflow seating. But a front row at 13-14' from (a itty bitty 100" wide screen,
for kids (who won't care if they are 7' from the screen), isn't my idea of good design.
Seven seats wide, you might want to carefully consider your speaker choices, so they have a nice wide dispersion.
Those 15 minutes on the forum, are getting you some feedback based on experience with lower headroom spaces, and even some
hard core home theater design course exposure. So I'd consider that a very smart move on your part....