Is it possible to get 50 Zygarde Cells before the Elite Four?

Question

Because at this rate Zygarde 10% isn't going anywhere fast, it's made of tissue paper.

Answer 1

It is very possible. It doesn't even take much work, I managed to get around 60 of the cells before facing the Elite 4 and I wasn't even looking for them.

87 of the cells are up for grabs before the Elite 4 (although two of those cells are found on Mount Lanakila, which is where the Pokemon League is located).

Answer 2

Yes. You can see the locations of Zygarde Cells here

Source: experience