Cisco ASR connected directly to two F5 (cluster)

From a design perspective if the Primary ASR router reboots/fails then your going to trigger a failover on the primary F5 if directly connected. I am not a big fan of swim lane design since 1 device failover can trigger another when directly connected. I would recommend you add a switch layer between the ASR's and F5's.

You can aggregate/trunk links from the F5 to switch (VLAN) and place the ASR links on that same VLAN as well. There are many different ways to go about this.

Are you planning on using L3 routing on the F5's to ASR's? You can aggregate multiple links to the ASR etc.