Amit it is not possible to configure LACP between three physically separate switches.
SRXs, your options are either MC-LAG or just regular layer 2 STP. Make sure you configure a layer 2 link between the 4600's trunking all of your VRRPed vlans.
Also, assuming your diagram is correct, your vlan tags are not matching up. xe-0/0/1 on the two 4600's is trunking vlan 232 but the 4300 is trunking vlans 7 and 240 on xe-0/2/0 and xe-2/2/0.