I'd like to make her birthday celebration a grand one.
I'd like to have a big birthday party for her with lots of people.
この場合、次のような言い方ができますよ。
ーI'd like to make her birthday celebration a grand one.
「彼女の誕生祝いを盛大なものにしたい」
a grand one「盛大なもの」
ーI'd like to have a big birthday party for her with lots of people.
「たくさんの人と彼女のために盛大な誕生日パーティーを開きたい」
a big birthday party で「盛大な誕生日パーティー」と言えます。
ご参考まで！
I hope us all to celebrate her birthday in as gorgeous a manner as possible.
I would like for us to celebrate her birthday in a grand style.
ご質問ありがとうございます。
① "I hope us all to celebrate her birthday in as gorgeous a manner as possible."＝「彼女の誕生日を出来るだけゴージャスに皆全員で祝ってあげたい。」
② "I would like for us to celebrate her birthday in a grand style."＝「彼女の誕生日をみんなで立派に祝ってあげたい。」
ご参考までに。
カナダ 
アメリカ合衆国 
