Plenty of dry grass clumps s great. Remember they come from some pretty dry, well grassed country. I like to provide plenty of dry gumleaf litter too. Logs, grass clumps, live Guinea grass, leaf litter...all good. Not too much clutter though, makes it too hard to keep clean.
Regarding compatibility, I always go by the motto; you need 3 pairs to get 1 good one. by all means, try a new male or female. When you have success, don't be in too great a hurry to sell the youngsters, keep some back for yourself and begin your own bloodline. Young birds that you have bred yourself are far better breeders, being acclimatised to your conditions and methods.
PS. Mine still not showing any interest in nesting. I will take a young pair to my mum's this afternoon and see if she can work her magic with them again. Last year she bred the majority of our LBQ

Her avairy is 3x5m Planted, leaf litter, full roofed.