Well Aika's solo line was given to Aichan and I guess now that Riho isn't in the group, most of Ai's lines have been given to Sakura.
Aika's 1st solo line in Egao Yes doesn't count as a solo line that Sakura inherited via Riho though because Riho never inherited Aika's 1st solo line in that song from Ai-chan. Sakura did because the next time they performed Egao YES after Ai-chan left was during the Michishige Eleven Soul tour: