1, 2: No, they are not.
3: Both cultivating jhāna and magga phala are purification of the mind (not involving akusala). Seeing adinava in raga leads to not having raga. We need to be aware that the absence of raga can help suppress and remove stress. Because some anariya yogis can also see adinava in kama raga and choose to attain jhana.
The difference between suppressing and removing lies in whether one understands the following things: (i) Without any exceptions, all sukha that comes from raga depends on sankhata. (ii) All sukha that depends on sankhata is never free from the three types of dukkha. (iii) Pursuing sukha by having raga is nothing more than shoveling sand against the tide.
(i)~(iii) are about an extension of the scope of seeing adinava to ALL of samsara. Magga phala require this point. On the other hand, jhāna only require seeing adinava in kamaloka. For that very reason, anariya jhāna can be broken.
4. : I never experienced jhana. But as far as I know, those are indistinguishable.
5. Can one develop supernormal powers (iddhi) by cultivating jhāna?
: I don’t think it’s possible to have iddhi if one only cultivates jhāna, but I think it is possible if one makes an additional and valid effort.
+) I’d like to share my experience somewhat related to.