What is 'ne'?
Plural of "se"
Can I say "ovatko HE tällä?" the English sentence is a bit unclear, not sure what to use for "they" here... he or ne? "?
You could say ovatko he tässä. Not sure though when you would ask that. Speaking of people you would more likely ask ovatko he täällä. But that is not the original sentence.
What is täällä used for?
'Tässä' is translated 'right here', and 'täällä' is translated 'over here'. 'Tässä' is closer than 'täällä'.
Why can't it be 'Ovatko tässä'?
Third-person pronouns are usually unomissible.
You're right, thank you! I forgot about that.
what is the difference betwenn "tuossa" and "tässä"
Tuossa means "right there" while tässä means "right here."
‘They’ does not specify if a person or thing so surely you could have ‘ovatko he tässä’ ?
"Ne" is used for both persons and things. But yes, "he" is an alternative.