は兎(と)も角(かく)Setting aside, Apart from

Both mean setting (A) aside and are often interchangeable. は別として can also mean except for (A), as in 彼を別として全員出席した (Everyone attended except him). はともかく simply sets something aside without excluding it, as in 値段はともかくデザインが好きだ (Setting aside the price, I like the design).

Both set aside one item to comment on another, but the nuance differs. はおろか emphasizes that something is far beyond expectation, often meaning ‘let alone,’ and highlights an extreme gap, as in 漢字はおろか、ひらがなも読めない ('He can’t read hiragana, let alone kanji.'). はともかく means ‘setting aside’ or ‘regardless of,’ used to temporarily bracket one point and move on without judging degree, as in 値段はともかく、味は悪くない ('Putting the price aside, the taste isn’t bad.').

はともかく and を除いて both suggest setting something aside, but with different nuance. はともかく downplays relevance to the main point, as in 田中さんはともかく、鈴木さんは来ると思う (I don’t know about Tanaka, but I think Suzuki will come). を除いて explicitly excludes something, as in 田中さんを除いて全員来ると思うよ (I think everyone will come except Tanaka).

Both mean setting (A) aside and are often interchangeable. はさておき・はさておいて is often used to temporarily set something aside to prioritize another point, as in 冗談はさておき本題に入りましょう (Jokes aside, let’s get to the main point). はともかく can dismiss something as irrelevant, as in 値段はともかくデザインが気に入った (Setting the price aside, I like the design).

はともかく carries the nuance of setting something aside to focus on the rest. For example, 田中さんはともかく、みんな来ると思う means 'Setting Tanaka aside, I think everyone will come.'. In contrast, いがい emphasizes exclusion, 田中さん以外はみんな来ると思う means 'I think everyone but Tanaka will come.' So, はともかく avoids commenting on Tanaka, while いがい explicitly excludes him.