Eleanor is totally alive. She couldn’t resist telling Eliza about the spa day stunt with “Stella” because she loves telling stories, especially stories with herself as the heroine. Telling these stories, as Stella, just adds to the Eleanor/Dorothy mythos. Eleanor also revealed how she switched places, causing Stella to be killed instead, although of course she can’t admit the truth, and is still claiming to be Stella.
I mean, “Stella” is pretty good at being the right place at the right time, and then slipping away without a trace. Sounds more like Eleanor, doesn’t it? Stella was part of Eleanor’s machinations, but she took a free spa trip when requested, there’s not evidence that she’s as sneaky as Eleanor.
Did you catch that line about Steadman’s shop burning down? Obviously, Eleanor! The only question is whether she did it wanting revenge but not realizing that Eliza doesn’t work there anymore or whether she did it to rescue Eliza from the fire, the same way she took care of Eliza in the hospital as a child… But she definitely burned it down.
Totally alive and up to her old tricks.