Logan Lerman gives Percy Jackson series his blessing, definitely won't be making a cameo
The actor denied, denied, denied in a recent red carpet appearance

Let’s get one thing out of the way: the original Percy Jackson And The Olympians movies (The Lightning Thief and Sea Of Monsters) were bad. Don’t just take our word for it; author Rick Riordan once referred to them as his “life’s work going through a meat grinder” in a now-deleted tweet. Now, a decade later, Riordan vowed to “fix it” and start fresh with his upcoming series on Disney Plus.
Yes, the new series will certainly be free of any reference to that dark era. A cameo by the original Percy, Logan Lerman, will absolutely not be happening. No, sir.
While promoting his new film, Bullet Train, Lerman was asked to comment on the upcoming series, about which he is “really excited.” He then specified that “everything [he has] seen so far, like peripherally, just about like casting and how they’re doing it and that Rick [Riordan] is running it… just makes [him] happy.”