1st of all, I wld like to say milk bottles is a personal thing. What 1 baby like might not be the same for another baby. I dont't have any comments on which one fits baby better cos my baby rejected all bottles.
I have avent & Pigeon bottles bcos of the breast pumps. For Avent, you need to buy back their accessories like sterilisers, bottle warmer, teats and caps cos their bottles are not standard size.
I use standard Piegon bpa free bottles with my breast pump (not a pigeon brand though).
For breast milk storage, you can opt for either bottles, milk bags or milk storage sys like the Avent Via cups.
For a start, I would suggest 4-6 bottles but again this depends on your cleaning pattern, eg do you only wash all used bottles together at the end of the day, or do you wash and sterilise after each feed. If you opt for 1st method, then you might need more than this no.