hi guys, i am a native Cantonese speaker. I bumped into this forum this morning, and am surprised that you guys are interested in Cantonese. :)
Regarding the question, actually most of your translation of 'wait a while' can be understood.
等一下: it's written form. It's a bit odd to be used in conversation. However, if you say 等下, it sounds more natural, and it is normally followed by an object/ something that's gonna happen.
等（一）陣間/ 等陣/ 等一陣: These are all correct.
Moreover, you may add a 先(sin) after the above phrases to make them feel more gentle. Ie. 等陣先/ 等等先
Hope it helps :)
Regarding the question, actually most of your translation of 'wait a while' can be understood.
等一下: it's written form. It's a bit odd to be used in conversation. However, if you say 等下, it sounds more natural, and it is normally followed by an object/ something that's gonna happen.
等（一）陣間/ 等陣/ 等一陣: These are all correct.
Moreover, you may add a 先(sin) after the above phrases to make them feel more gentle. Ie. 等陣先/ 等等先
Hope it helps :)