Does the presence of moisture upon waking necessitate ghusl even if one does not recall a wet dream, and do discharges that exit with pleasure necessitate ghusl if not followed by the subsidence of that pleasure?

Ghusl (ritual bath) is only obligatory when one is certain of the emission of semen, which necessitates ghusl. So, if you had a wet dream but did not see semen, ghusl is not required of you. As for the discharges emitted with desire, they are either semen, which necessitates ghusl, or pre-seminal fluid (madhy), which requires cleansing the area and performing ablution (wudu) for prayer. If you are uncertain whether it is semen or madhy, you have the choice to assign it the ruling of whichever you wish.