Translation:Here come all the emotions all at once.
It is also quite common in English to use the expression at one and the same time to emphasize the simultaneity, but it doesn't seem to be accepted as a correct answer in DL.
Yes, I put "here come all the emotions at one and the same time" and duo told me to I should say: Here come all the emotions at the same time. It seems the same to me.
Yes, "one and the same time" is a perfectly acceptable English expression and seems to mirror the Swedish exactly, so I don't see why it shouldn't be accepted.
I have added this now, plus about half a dozen other perfectly fine translations. :)
Do you think "feelings" could be used in place of "emotions" in the English translation?
'Eleverna kom på en och samma gång' is this a correct use of the phrase?
Yes, but this en och samma puts a strong emphasis on it being simultaneous, so you'd usually just say Eleverna kom på samma gång. Or even better, Eleverna kom samtidigt.
I thought when action is involved, hit should be used instead of här. Or is it so that här here is used as an subject, similar to det?
Yes, I think the comparison with det is very good. This sentence does not mean that the feelings are 'coming here' as in 'coming to me' in a directional sense. One could just as well have said Nu kommer alla känslorna. ('now' could have fulfilled much the same function).