personally I prefer to keep my breeding females seperate as they don't always get on and dominance/stress problems can arise especially during breeding season with regards to laying boxes and food ~
if the new female has already finished a quarentine period then if you must put her with your other female then I would do so in a clean viv with all furnishings cleaned of any scent's from the main female ~ however I would not re-introduce the male until he's needed next season as the new female especially will be under enough stress with new surroundings as will the old female plus they will also have the possible stress of sorting out who's dominant.
I would also advise that a spare set-up be kept incase the females start fighting or dominance/bullying issues stress one too much....... bullying etc doesn't always take shape in physical fighting ~ there's a study I did on leo behaviour on my website which may be worth reading.
I know both Jools and Olivine like myself are kept busy IRL and we don't always have time or chance to read through various posts
