According to the most recent news on shinki-net site and Battle Rondo updater, Nurse Type Brightfeather, Sister Type Harmony Grace, Chopstick Type Kohiru and Spoon Type Merienda are all coming to Battle Rondo, and quite soon at that!

Here's a copy paste of the official announcement:

2011.03.30 10:00 臨時メンテナンス/対応キャラクター追加のお知らせ
11.03.28
2011.03.30 10:00～14:00の間、臨時メンテナンスを実施し、以下の神姫をバトルロンドに対応いたします。

【バトルロンド】
　・ナース型ブライトフェザー
　・シスター型ハーモニーグレイス
　・箸型こひる
　・スプーン型メリエンダ

※メンテナンス中は、武装神姫ジオラマスタジオ、バトルロンドはご利用いただけません。
※作業状況によっては、メンテナンス終了時刻が前後する可能性がございます。

Which basically reads that between 10:00 ~ 14:00 they'll be implementing the characters on the 30th. Feel free to correct me if I'm wrong.
Edit: There are pictures, only in the shop, no banner yet.

http://www.shinki-net.konami.jp/shop/item1103.html

Yayyy , Ty for the news Perso!
I think AK will be very happy about Kohiru!

...Wow, they're on a roll.

Whoa, neat. I've actually been playing BR a bit again too.

Any news on VAs?

Caterwaul wrote:Any news on VAs?

Haven't found any yet. Will update if found out though.

great!!! been wanting Harmony Grace in action!!

btw, is Lavina and Tempesta goin in as well?

Lavina and Tempesta didn't come with codes, so I really doubt it :/

Mikuo_Hatsune wrote:Yayyy , Ty for the news Perso!
I think AK will be very happy about Kohiru!

You bet I am! About time! My team is now complete on Rondo. Well, almost. I got a headless Tsugu lol.

And they should now get Benio, Kohiru, and Tsugaru into Battle Masters so I can command them on the go......Do it! Konami! Do it!

---

Edit: Here is my Kohiru and a placeholder for now:
- http://twitpic.com/4evgwl - HAI!~