Hello Alan,
It all depends on your deployment, if you are setting up these 2 APs to only bridge 2 sites wirelessly then you don't really need a virtual controller; however, if you have multiple APs you'd like the AP8432 to adopt, then you can turn it into a virtual controller. Make sure you configure the AnyAP profile for heterogeneous AP adoption.
In other words, a VC is not a must for meshconnex to work, but you can configure this setting should you like all APs adopted by VC.
https://gtacknowledge.extremenetworks.com/articles/Q_A/Unable-to-adopt-heterogeneous-different-APs-by-my-WiNG-virtual-controller
Thank you,
Chris
Christoph S.