The Cruiserweight Championship match for SummerSlam should be set after this week's episode of 205 Live. PWInsider is reporting that this week's show will be headlined by Ariya Daivari vs. Akira Tozawa and the winner will go on to face Neville for the title at SummerSlam.
They've been pushing Daivari in recent weeks so it would not shock me if they did something to make it a Triple Threat Match.
The following matches have already been officially announced for SummerSlam:
Jinder Mahal vs. the winner of the John Cena/Shinsuke Nakmamura match on Smackdown Live
Smackdown Women's Championship
Naomi (Champion) vs. Natalya
Raw Women's Championship
Alexa Bliss (Champion) vs. Bayley