Yes, you can run two PLA filaments & print two-tone, which will be fun in the fullness of time. I'm sure you'll be fine with picture glass, but if the heat does eventually get to it, search ebay for Boro - you can get it much cheaper from China than from within the UK.
I bought a can of supermarket own-brand 'firm hold' hairspray and that seems to be helping considerably. It's not perfect - I've still got issues with edges curling up - but it's a lot better. Currently printing this
Iris Box