@Rick Morris
I haven't done this before , and is challenging and worth looking into by simulating this in LAB environment , due to the fact that syslog command doesn't seem to allow VPN ports unless NAT-T port 4500 which falls within the port range.
Normally I view this logs through vpn-sessiondb command , and looking at the documentation on this , it falls back to the ASA command I was thinking of which is :
logging host interface_name syslog_ip [ tcp [/ port ] | udp [/ port ] [ format emblem ]]
But the above command only acknowledge a certain range or port according to documentation (1025-65535), in this case only NAT-T port falls within this range which is 4500 not isakmp 500 or IPsec 50 or 51. Please refer to this link https://www.cisco.com/c/en/us/td/docs/security/asa/asa90/configuration/guide/asa_90_cli_config/monitor_syslog.html#68764
But really if the details stated in your question you want to log , I will just go for the vpn-sessiondb ra and copy from there. Let me know if this help ......