Good question. I'm not too savvy on ultralights, but here are some thoughts to get you pointed in the right direction...

Ultralights and powered parachutes did not really use to be covered by the FARs as far as pilot certification goes (ie no pilot certificates existed for them) but the recent Light Sport Aircraft initiative has created an LSA pilot cert which includes ultralights and powered parachutes. I'm not sure of the details but I know folks with previous experience are grandfathered.

But since the LS license is similar to a PPL as far as privileges go, I would assume that you cannot carry pax for hire with just a a LS license.

The SP CFI ticket CAN be acquired without a CPL, you just need a SP certificate. That clearly implies that you can teach in LSAs without a CPL, but does NOT imply that you can carry pax for hire (other than a student).

The new regs kind of make me suspect that a regular CPL would be required for a charter or sight-seeing business. However...I'm not sure an aircraft certified as LSA could be legally used to carry pax for hire?

Since a PPC is formally listed as a separate aircraft category, PPC flight time would not count towards all of the CPL experience requirements in another category...ie airplane. But I THINK that it would count towards some of the required time (you still need a certain amount in category).