I have a CRUZ and am looking at buying a VISTA.... Can I use my CRUZ seat as the second seat on the VISTA?

The answer is NO - whilst this seat will fit on the lower adapters, it is not tested on the VISTA and will void the warranty of the pram. 

The ALTA/CRUZ seat was NOT designed to sit on the lower adapters and the lower adapters were not designed to hold the weight of a toddler. This is also incredibly UNSAFE for your child. Please do NOT try this configuration. 

If you are looking at transporting two toddlers on the VISTA please purchase the additional Rumbleseat which has been designed and tested to sit on the lower position of the pram!