Family Trip - traveling with a one year old

The logistics of traveling with 7 folks is tough enough without one of them being a one year old. By all means, rent an apartment(s) that has a washing machine. It will allow everyone to travel with much less luggage--possibly half the clothes vs. no washing machine. It's especially important for those traveling in groups to adhere to Less is Better--like in Rick Steves' Packing List.

Portugal is not that large of a country. It might be best to find a central location and do day trips--not moving around.
It also might be preferable if your group rented two smaller cars instead of a big (and expensive) van. That would give the group the ability to split up and go their own way, especially in hours where the baby will be napping.

We traveled with our then 1.5 year old grandson and his parents to London and Wales in June 2018. Plan on on plenty of downtime, possibly an extra nap, sleeping through some of the sites, wanting to do things where he/she sees other children playing and mom or dad staying with the child while the rest of you go out to eat. If you are going to travel by car, plan on carrying a car seat with you. We traveled only by train or the tube so they did not need a car seat. Also, his parents used a child back pack carrier for many of our venues. They did not bring a stroller. His parents then took him to Portugal last January at the age of 2 and their itinerary included Lisbon, Porto and Coimbra. He handled it well. However you set up your itinerary, plan one venue / activity in the morning and one in the afternoon. FYI, we all traveled with carry on only, had laundry done along the way at a wash and fold laundromat.