Nobody

The chiseled characters on the tang are imperfect because of wear and tear. But I think that the second kanji looks like 継 (tsugu). The name may be 義継 – Yoshitsugu. FYI: yoshtsug.jpg (91×250)

It must be a typo. 純正眞鐵入鍛 I do not know its correct reading either. Junsei magane nyutan (?) - Forged from genuin iron.

Just a guess, 蓋好資料之一也 (Kedashi ko-shiryo no hitotsu nari) – Probably, it is one of good examples. 金象嵌 銘曰 ＊ kin-zogan mei iwaku

小林 - Kobayashi (family name)

I think that your reading is correct. The nuance of "... saku ka" is conjecture rather than doubt.

大谷家之紋透鐔 (Ohtani-ke no mon sukashi tsuba) – Sukashi tsuba of Ohtani family’s mon IMO, the hanging wisteria crest on the tsuba looks a little different from the Ohtani’s Sgari Fuji.

東神正国作 – Toshin Masakuni saku 昭和十九年三月日 – Showa 19th year (1944), 3rd month

蓋同銘中無出其右者 (Kedashi domeichu sono migini derumono nashi.) – Perhaps, among the works with the same mei, it is second to none. As for “盡忠則命” on the box, I think that we do not have to be too bound by the word on the box. I guess that the order of the kanji was Kanzan’s own understanding only because he did not know the original four-character idiom 忠則盡命. The attached article was written on the premise that the word was 忠則盡命. Ref. 忠則藎命図鐔　銘　三信家

萬延元庚申年日 – Man’en 1st Kanoe-Saru year (1860) 鈴木鉄造典直迮之 – Suzuki Tetsuzo Norichika/Norinao made this.

下原住正長 - Shitahara ju Masanaga

On the wakizashi, 國安 - Kuniyasu

勝正 - Katsumasa

I am unsure about the second line. It might be an address? 祈願武運長久 – Pray for continued luck in the fortunes of war □□□□□□□ 谷口幸雄 – Taniguchi Yukio 二十二才 – 22 year old

99% gimei, 住東叡山忍岡邊 – Living in Toeizan Shinobugaoka no hotori, 長曽祢興里作 – Nagasone Okisato made. 於小塚原二ツ胴敷碗落之 – At Kozukahara, two bodies and forearms were cut. 寛文拾貮年八月日 – Kanbun 12th year (1672), 8th month

That is correct. I had this sayagaki written in October 2000. The description is simple, and the characters are written in Block script.