1. You can find this info at easyjet.com. And the answer is: no! I think your backpack is bigger as 56 x 45 x 25 cm. Hikingpoles are not alowed in the cabine!
2. Do you mean Algeiras? That's 8km's from Porto. (http://www.campings.com/portugal/porto/camping-porto.htm)
Just walk, the camino will...