Guest restrictions who to invite?

[Sunshine51]

Only 20 places on Ds birthday have filled 19.
Who to give last place to? my friend daughter who he has met once but went to her party.
A child from nursery who invited him to theirs or a child ds gas chosen from nursery.
He will be 3 years old and is having a toddler sense party. What is the etiquette?

I would invite your friend's daughter as she is a little closer to you than nursery friends and you would see her socially more often.