Taylor triggers earlier, and under different circumstances, thus gaining a different power: Administration of the Senses. She can perceive though the senses of living things around her (including senses like
proprioception, that tend to get ignored in stories like this, as well as parahuman abilities), has supermultitasking to help deal with that, and can influence what people in her range perceive. She doesn't have total control over the senses of others, especially not at first, but can give general instructions making targets hallucinate something (the victims' minds interpret the instructions, though something like 'you don't notice me' works pretty consistently); since she can see (or hear, or whichever) what her victims do, she can adjust her orders on the fly. With more practice, she can give more complex instructions with better control, and the more she knows a specific target, the better she can tailor their hallucinations. She has a bit more control over dreams, but even there, things are open to interpretation.
Gaslighting Emma, for example, is fairly easy, and gets easier as she begins to understands how her friend has changed. Gaslighting Sophia is rather trickier, but since she's smarter and more creative than Sophia, and Sophia is not mentally prepared for this sort of opponent, she can still do pretty well. It helps that this is before Sophia got caught by the PRT, and Stalker is both too confident and too distrustful of authority to go to them.