If you get Ronnie and the Professor (Martin), then i can't see them beating Count. It takes an entire Avengers team to take him down, and even then they only barely do it.
He's survived a phasing by the Vision, and even denied it.
Durable enough (understatement) for Thor's hammer to do nothing to him
Strength feat (can Firestorm get anything off before he creates a shock wave stronger than anything the Hulk can do?) If Jason is involved, how will he concentrate enough to transmute Count when this is continuously going on?
He has some energy absorption/control powers of his own
Nefaria has also discovered that he can control other ionic powered beings. Nefaria also apparently has a great degree of regenerative powers, as he was able to survive apparently being blown to atoms.
And he's quite fast, i do wonder if he could speedblitz Jason before they can transmute him, when looking at this.
W/o the GL ring Mon-El is strong enough to challenge Kyle. He is Supes-level in terms of speed, strength, heat vision, etc. and has fought and suceeded against people like Lobo w/o his ring. He is faster in combat than Kyle and has way better reaction time plus has physical strength to rely on. The ring just gives him even more power to play with. Kyle is more skilled with the ring obviously but Mon-El doesn't have to worry about running out of power because he always has his physical powers to fall back on. I think the fight is a back and forth between the two for a while but eventually Mon-El will wear down Kyle's shields and ring power and then KO him. Mon-El could spend the majority of the fight just using his physical powers and then save his ring energy for the final blow.
Mon-El is equal to Supes so its a close fight if Mon-El was only fighting him with his Daxamite powers. The GL ring swings it in Mon-El's favor tho.