>>80135956In terms of general popularity it would be Mumei. Even without streaming much, many events or released music, she is still insanely popular, with good merch and all.
Bae focused a lot on idol side of things the past year, which finally increased her popularity; moving to Japan also helped.
Fauna is the most watched on the regular, with very strong SC and merch game, but lacking in music and idol activity department due to her health and insecurities about singing skills.
IRyS is great at singing, but because of severe mismanagement over the years her career in that direction mostly died, she still gets good viewership and is up there with Fauna in terms of SC.
Kronii had the biggest potential at debut, but she manager to sabotage herself in various ways. While still popular, I wouldn't say she excels in any area at the moment.
Even Mumei wouldn't be Gura/FWMC tier ace, but as a gen they seem more well rounded than other gens. All above average, but without a single breakout talent that becomes the face of the gen.