Can paper napkins and tablecloths be considered as bio- waste disposal?

Paper napkins and tablecloths, especially with food stains, can be considered bio- waste disposal, if coming in moderate quantities.As a matter of fact even the paper is biodegradable.

Where can I dispose of transparent glasses made of PLA?

The technical term is polymer of lactic acid and comes from the fermentation of a sugar corn. It isn't plastic, but it has all the characteristics of strength and ductility. You can throw it away with bio- waste because it is 100% biodegradable and compostable so it can be digested by bacteria in the soil.

Is a transparent PLA glass as resistant as a plastic glass?

PLA glasses have the same characteristics of traditional plastic glasses, they are very resistant and ensure optimum performance. They can be filled in with cold drinks and hot drinks ( up to 50 C°).