The audio here rises in intonation as if this were a question. Is that normal for statements in colloquial speech, or was it read incorrectly?
The TTS reads it wrong - should be no rise in intonation.
Could this be a group of both male and female students or only all male?
it's either a male group only, or a male and female one
Audio comes across as a question due to intonation. Is this just how native speakers speak? If so I need to adjust my perception when listening
Unfortunately, the intonation is frequently wrong. Text-to-Speech isn't perfect, to make it so someone would have to record themselves saying all those sentences.
Where is the difference between present progressive and simple present in polish?
For 99% of the verbs, there is none, both are correct translations. Most of the verbs that have it (different verbs are used for those tenses) are Verbs of Motion.