Channel 5 is owned by Viacom which also owns MTV. Ex on the Beach and Geordie Shore air on MTV alongside CBB repeats so by putting the cast on CBB is basically self promotion for the parent company.
Because she's nice really, but when someone crosses her she'll unleash her inner shade beast. I think she has grown up since Flavor of Love and it was a totally different show; a group of several women fighting over one man.