Hi Laurah,
I don't know if i've missed some of your posts, but you don't say what time of the year you're walking The Camino. The thought of carting a bivvy and all those bottles of multi use soap is scary. I am older, but even in my younger days i travelled light. You should not have problems staying in hostels, so i would prefer a sleeping back and thermals if you travel in cooler weather. Coming fronm Midwestern Australia i feel the cold, and a polar fleece jacket was a goodsend, lightweight warm and quick drying. I walked in july last year and i had a heatwave, pouring rain and cold.
I suggest if your Daughter wants to join you she saves up her own fare if she's old enough If you are taking 3 monthsyou are taking your time, so maybe extra weight won't bother you.
I managed very well on my budget, the gin and tonics where my biggest expense.
Buen Camino