With the recent announcements, I feel like the chances of Atobe playing D1 against Germany have increased significantly. For one, he's featured on the volume 31 cover. While being on the cover isn't a guarantee that the character will also have a match around that time, there's a pretty strong correlation. Also, if Atobe does play D1, he can get his power-up just in time for the Rikkai vs Hyoutei OVAs, which start releasing in February or March.
As for potential partners, I guess Irie is the most obvious pick, but I'm not a big fan of that pair, so I wouldn't mind someone else. From the HSers, Byoudouin, Tanegashima and Ochi seem like the easiest alternatives. But, if Konomi wants to tie in with the OVAs some more, Oshitari and Kirihara are viable candidates as well.
As for potential partners, I guess Irie is the most obvious pick, but I'm not a big fan of that pair, so I wouldn't mind someone else. From the HSers, Byoudouin, Tanegashima and Ochi seem like the easiest alternatives. But, if Konomi wants to tie in with the OVAs some more, Oshitari and Kirihara are viable candidates as well.