Is Sero a name you just thought up? Because when I looked around on jisho.org, I couldn't find any kanji combos for Sero, only Serona.
In regards to which names pair up best with Sero, my top picks are
Miyu (実優 - reality/truth, actor/excel/gentleness) &
Sōta (創太 - genesis/originate, big around/plump/thick).
May I suggest a couple of suggestions for your main character, her siblings & her father:
Main character:Kanade [奏 - complete/play music] (ka-na-de)
Narumi [也美 - to be, beautiful] (na-ṙuy-mee/na-luy-mee)
Nene [寧々 - preferably/rather, 々 is a kanji repeater] (ne-ne)
Hazuki/Hadzuki [葉月 - leaf/plane/spear, month/moon - traditional name for
August] (ha-dzuy-kee/ha-zuy-kee)
Siblings:Chiharu [千春 - thousand, spring (season)] (chee-ha-ṙuy/chee-ha-luy)
Himawari [向日葵 - approach/beyond/defy, day/sun, hollyhock - word for 'sunflower'] (hee-ma-wa-ṙee, hee-ma-wa-lee)
Misuzu [三鈴 - three, buzzer/small bell] (mee-suy-dzuy/mee-suy-zuy)
Shin'nosuke [慎之介 - be careful/humility, of/this, jammed in/mediate] (sheen-no-ske)
Masakazu [正和 - correct/justice/righteous, harmony/peace/soften] (ma-sa-ka-dzuy/ma-sa-ka-zuy)
Tetsurō [哲朗 - clear/philosophy, bright/cheerful/clear] (te-tsuy-ṙo:/te-tsuy-lo:)
Father:Hideshi [秀士 - beauty/excel/surpass, gentleman/samurai] (hee-de-shee)
Manabu [学 - learning, science, study] (ma-na-buy)
Naoki [尚樹 - esteem/furthermore, wood] (na-o-kee)
Tsutomu [勤 - diligence, serve] (tsto-muy/tsuy-to-muy)
--All of the pronunciations that I've put up were used from the BtN pronunciation guide--
By the way, is her mother involved in the story in any way? I have some names for her mother that I can share with you.
My PNL:
http://www.behindthename.com/pnl/149249