Hi Rajiv,
Below is a link to an article that provides a basic VRRP configuration for both switches.
https://gtacknowledge.extremenetworks.com/articles/Solution/Configuring-VRRP-and-VLAN-tracking
Switch A would be BD8K #1 and Switch B would be BD8K #2.
A LAG, static or using LACP is good for redundancy/bandwidth purposes used between the BD8K switches. There should not be problem using LACP between the switches.
For the edge switch connectivity to the BD8K switches, customers use two uplink ports (one going to each BD8K). For example, if the x450 has uplink ports 46 and 48, 46 can be connected to BD8K #1 and 46 connected to BD8K #2. In VRRP active/standby mode, a VLAN's traffic from the x450 will be sent to the VRRP master VIP address for that VLAN. If switch A is the VRRP master, then the x450 traffic will be sent to switch A for that VLAN. If there is a problem on switch A preventing the VRRP hellos to be received and processed by the VRRP standby switch, the standby switch (switch will assume VRRP mastership for that VLAN and the x450 traffic will begin to be sent to switch B for that VLAN.
Hope this helps.
Regards
Tony