you already know echo and Liam, there's their dad who is the cause of this whole story and the whole plot is his fault (and who also at some point gets corrupted and becomes the villian),

there's echo's boyfriend who doesn't have a name yet- but he is very artistic, he doesn't really get good grades, and he's also Liam's best friend (or at least he WAS, Liam gets a new best friend later cuz drama yes)

and we have Eliza! (name might change) a character from the past, the first person Liam meets when he actually learns how to use his powers, she is a servant in a palace where someone died by poison and people are trying to figure out who did it, Eliza and Liam solve the mystery before the timeline gets messed up and they have to travel back to the future to fix it (with echo)

I wanted to add echo's beloved first robot or the kid that follows them around everywhere but I was like "nah" so there's that