I took a crack at the weird credits:
プログラマ さだもん と がーふあんくる
Programmers: Sadamon and Garfunkel
(This one's fine.)
はかせ と その かよいづま
The Professor and His Long-Distance Wife
デザイナー あべる あべれば あべるとき
Designer(s): Fatty McFatfat
//あべる is apparently an alternate reading of 太る.
プランナー かある くらうざあ いのまた
Planner(s): Karl Klauser Inomata
サッキョク だんじり だんじり くむくむ
Composer(s): Danjiri Kum-Kum
//I think this name is a combination of Danjiri (from Danjiri Festivals) and Kum-Kum, the protagonist of a really old anime.
ガンバッタ みにもん ぼん おーちゃんず
Special Thanks: Minimon Bon Ochanzu
くりながサナタール($30)マサユキ
Masayuki "Thanatar" Kurinaga
//I think "Thanatar" is a reference to RuneQuest.
だめいじでざいなあ かーさき
Damage Designer Kasaki
かきこみジユウな てっちゃん
Scribblin' Tecchan
べじたぶるどらんかあひろりん
Vegetable Drinker Hirorin
しかけにんたちとうさぎちゃん[ED]
Bunny and the Gang
Edit:
As for the two item names, you're overthinking とくべつれいのふく. It's definitely 特別霊の服. I'd go all SaGa Frontier and translate it as "Spiritwear."

たまごだん is a bit trickier. As a suffix, 弾 is pretty generic. It can mean "bullet," "bomb," "flare," or even "grenade." More importantly, though, chicken eggs are said to stun or harm Jiang Shi. I would just go with "Egg" or "Hen's Egg" in this case.