Your private space is not a lawless space! Going to construction with three people probably isn't allowed either! If the buddy were family again, then it would be legally okay again.
Only if they share a household, otherwise not okay again
Your private space is not a lawless space! Presumably, going to the construction site with three people is also not allowed! If the friend were family again, then it would be legally okay again.
GG Art. 13 still applies. You can invite 10 friends into your apartment, the limit of 2 persons only applies in public spaces. Whether a construction site can be considered a residence is, in my view, at least questionable. Are you sure that the schedule of the following trades can be maintained? It seems that at the moment everything is going differently than planned.
I'll join in here. Three to four people, each with a maximum of two in two apartments on the ground floor and upper floor, would still be okay? What is your assessment of that? Olli