As regards air, only AirFrance.fr operate direct daily services between Lisbon and Bordeaux but the one way prices are high. You might get a better deal buying a return and not using the return sector.
Easyjet.com have just launched a flight from Lisbon to Lyon. They also operate Lyon to Bordeaux. You might find this useful.
As regards Brittany, it is very difficult. My partner and I had to visit friends near Carhaix, over Christmas and after hours of working on flight combinations from Faro and Lisbon, I ended up hiring a car and driving.
Another option would probably be from Lisbon via a UK airport (either London Gatwick / London Stansted or Bristol) on Easyjet.com or a combination of Easyjet / Ryanair.
A final option could be by Easyjet.comm - Lisbon to Paris Charles De Gaulle and then TGV train from Charles de Gaulle to your destination. See www.sncf.fr for more information.
Be aware that you may have to spend a night en route.
