動詞可能形 ＋ 〜ものなら： 〜ことが可能なら （実現が難しいことについて言うことが多い） "If only I could/may...,"
〜う／ようものなら： もし〜ようなことをしたら．．．（大変なことになる） Once if (one) happen to ... , then (bad consequence)."
Used when one wishes to do something difficult. Usually used together with the potential form.
"if" does not quite get you there. For example, "If I come home late, he won't let me in" should perhaps be "Would I come home late, he won't let me in the house." ものなら is not iffy.
ex #3724 has nothing to do with this grammar point. 甘いもの (= sweets) just happens to be suffixed with なら (group 3)
Shouldn't ex #3722 be better translated as: "Whatever you pick for me is fine"?
-ようものなら is quite iffy. it denotes a hypothetical condition. [if i came home late, he wouldn't let me in]
ex #3719 is 〜もの(thing) ＋ ならば, and therefore does not belong to the usage of 〜ものなら . From ex#3719 to ex#3724, it doesn't give the meaning or correct usage of 〜ものなら, therefore treat it as 〜もの ＋ なら。 〜ものなら always follow the 可能形 potential form. and used to indicate something difficult to realize, or some ideal thinking of the writer,e.g. : "If only i was still a child, ...."
ex #3228 belongs to 〜う／ようものなら: My father is very strict. Once if I happen to come home late, my dad won't let me in.
〜ものなら： "If only I could/may.....", "If only it was possible to ....", "If only it was possible that..."
Added ex #5896 for 〜ようものなら
Do we need both #3717 and #3718? I don't see why the same sentence is listed twice because of one kanji...