Hmmm, very nice choices to be sure ;)
I'm still not sure I'd call them a "Line" unit, but, yeah, they could be the PointMan in an otherwise heavy lance.
When I think "Line", I think mid-speed (4/6) Upper-End Heavy, with lots of Armor & Guns.
The above Mediums are awesome units, but I'd still probably call them "skirmishers" v/s "line" units.