The Seuss pad can only fit really one decent-sized attraction. I'd say Grinch and Lorax are different enough in tone/setting that they each could warrant their own D-ticket/E-ticket.
Ideally, a Seuss expansion/revamp would be:
Seuss Landing
CitH upgrade/overhaul
Lorax dark ride (plot next to Cat)
Grinchmas soundstage turned into permanent Seuss show (changed for Grinchmas, of course... plus Halloween overlay, too)
Seuss Trolley upgrade (reworked to have 34" height requirement, more sets/AAs)
If I Ran the Zoo upgrade/refurb
Whoville
Grinch E-ticket family coaster (Poseidon's spot)
Horton/Nool restaurant (Mythos' spot)
The rest of LC would go to Potter. Malfoy Manor is a good idea for a Omnimover-style attraction.