Because both of them love nature.
Every female hamster there is except for his sister.........
No, Bebe actually likes Kyle, They kissed in the episode "clubhouses" Kyle does like bebe too, but he dosent show it all the time :)
No he care's for nures-chan/flora.
Yes, their friendship is clearly existant but because of Cartman's personality it is very tense at times and most conflicts between the two occur when Stan is taking the role of 'the Jew's lackey'...