Nobody

左近将監藤原盛綱作 – Sakon no shogen Fujiwara Moritsuna saku An honorable title in this mei 左近将監 (Sakon no shogen) - Lieutenant of the Left Division of the Inner Palace Guards

Not "menuki", but "mekugi".

As a side note, “東洋刃物株式會社” is a proper noun, and it has a specific English name. 東洋刃物株式會社 – Toyo Knife Co., Ltd. Ref. TOYO KNIFE CO., LTD.

There is no way it is 2 million yen.

春明法眼 - Haruaki Hogen

Of course, you know this, right? e-Museum National Treasures & Important Cultural Properties of National Institutes for Cultural Heritage, Japan e-Museum - Swords

鉄元堂- Tetsugendo 尚房 - Naofusa

The first part of the date desicription is 旹秊. 旹秊 (Jinen) – the year 旹 and 秊 are variations of 時 and 年 respectively.

Allow me to correct only one character. 九字銘有之而製作年紀ガ消サレ二月日ノミ残存ス a nine Kanji signature with its date erased (or faded?), only “a day in February” remaining

The Cultural Properties Protection Law took effect in 1950. And the tanto Inaba Shizu became a Juyo Bunkazai. Ref. 稲葉志津 - Wikipedia (Only Japanese language available) The following part is extracted and auto translated. ================================================================= On December 20, 1934 (Showa 9), it was designated an Important Art Piece under the name of Marquis Naganari Kuroda. Subsequently, on May 27, 1939 (Showa 14), under the same name, it was designated as a National Treasure (formerly a National Treasure) under the National Treasure Preservation Law. After the enforcement of the Postwar Cultural Properties Protection Law, it was designated as an Important Cultural Property, and since then, it has been owned by an individual in Aichi Prefecture, leaving the Fukuoka Kuroda family. ======================================================

Today I visited a friend of mine. His wife is a professional calligrapher, and I asked her about the third kanji in this phrase. “★★★作之珍重 ＊ ??? no chinch” She could not decipher the kanji with confidence either. But her guess was 孔. Assuming that the kanji is 孔, the phrase may be like this. 面白孔作之珍重 (Omoshiro ki ana no saku, kore chinch.) – The work with interesting holes, it is valuable.

佐藤兼住 - Sato Kanezumi He was one of WWII swordsmiths in Seki.

The second kanji is 乾 as @MauroP said. I cannot decipher the first kanji. I thought it looked like 夲 ( 夲 - Wiktionary, the free dictionary ). However, even if it is 夲, I cannot understand 夲乾.

I cannot see a gourd, but two horses. Willow and horses design seems to be one of popular themes for paintings. Ref. 日本刀販売・買取の銀座長州屋｜名刀鑑賞ガイド　金銅単鳳環頭大刀柄頭 Ref. 柳に馬 - Google 検索

行年七十才 – 70 years old 堀江興成 – Horie Okinari