Dear Palustris,
I think the seedlings are Alliaria petiolata, a native plant. However, the first leaves are not quite lobed yet but the colyledons are, for me, like Alliaria and also your clues "pinkish tinge" and "coming up in one place" is typical for Alliaria.
If the identity is correct, do not wipe them out all as the plants are host for the beautiful butterfly Anthocharis cardamines.
Wim