Very funny person, last to come to the fore in small group (4)
I believe the answer is:
trio
'small group' is the definition.
(group of three people)
'very funny person last to come to the fore' is the wordplay.
'very funny person' becomes 'rio' (I can't explain this - if you can you should give a lot more credence to this answer).
'last' becomes 't' (I've seen this in other clues).
'to come to the fore' is a charade indicator (letters next to each other).
'rio' put after 't' is 'TRIO'.
'in' is the link.
(Other definitions for trio that I've seen before include "Riot (anag)" , "Piece for three players" , "Beethoven's 'Archduke', for instance" , "Ensemble musical piece, eg Beethoven's 'Archduke'" , "wise men?" .)