AFAIK all non-Schengen arrivals at LIS are treated as unclean, meaning that they are physically separated from departing pax (Schengen or non-Schengen) until landside or after clearing transfer security. (This is the case in FRA and other EU airports for some but not all non-Schengen arrivals too.) So the only place where you could meet up is in the landside arrivals hall, which will be cutting it way too close IMO unless your friend arrives early and there are minimal lines at passport control.

Bottom line: I would not count on being able to meet your friend under the circumstances you described. Plan on finding another way to exchange the documents.