Explanation
The log type that will help the engineer verify whether packet buffer protection was activated is Threat Logs.
Threat Logs are logs generated by the Palo Alto Networks firewall when it detects a malicious activity on the network. These logs contain information about the source, destination, and type of threat detected. They also contain information about the packet buffer protection that was activated in response to the detected threat.
This information can help the engineer verify that packet buffer protection was activated and determine which actions were taken in response to the detected threat.
Packet buffer protection is a feature that prevents packet buffer exhaustion by dropping packets, discarding sessions, or blocking source IP addresses when the packet buffer utilization exceeds a certain threshold. The firewall records these events in the threat log with different threat IDs and names1. The system log also records an alert event when the packet buffer congestion reaches the alert threshold2. The other types of logs do not show packet buffer protection events. References:
https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/zone-protection-and-dos-protection/zone-defense/p
2:
https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/monitoring/use-syslog-for-monitoring/syslog-field

Explanation
https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/networking/configure-interfaces/virtual-wire-interfa
"The virtual wire supports blocking or allowing traffic based on virtual LAN (VLAN) tags, in addition to supporting security policy rules, App-ID, Content-ID, User-ID, decryption, LLDP, active/passive and active/active HA, QoS, zone protection (with some exceptions), non-IP protocol protection, DoS protection, packet buffer protection, tunnel content inspection, and NAT."

Explanation
Template variables are placeholders that you can use in a template or a template stack to represent values that differ across firewalls, such as IP addresses, hostnames, or interface names. Template variables allow you to create a single network configuration that can be reused repeatedly for large-scale deployments even if values of configured objects change1. Option A is incorrect because template stacks are used to group multiple templates together and apply them to firewalls or device groups. Template stacks do not allow you to use variables for different values2. Option C is incorrect because the Shared device group is used to push policies and objects that are common across all firewalls managed by Panorama. The Shared device group does not allow you to use variables for different values . Option D is incorrect because a device group is used to group firewalls that require similar policies and objects. A device group does not allow you to use variables for different values3.

Explanation
Option A is correct because setting "Reject Non-syn-TCP" to No and "Asymmetric Path" to Bypass in the Zone Protection profile disables the TCP checks that can cause the firewall to drop packets due to asymmetric routing. This allows the firewall to accept non-SYN TCP packets without a session match and packets that are out of sequence or out of window.
Option D is correct because setting session tcp-reject-non-syn to no in the CLI also disables the TCP checks that can cause the firewall to drop packets due to asymmetric routing. This allows the firewall to accept non-SYN TCP packets without a session match and packets that are out of sequence or out of window.
Option B is incorrect because setting session tcp-reject-non-syn to no in the CLI has the same effect as setting "Reject Non-syn-TCP" to No in the Zone Protection profile, so there is no need to do both. Also, setting "Asymmetric Path" to Global in the Zone Protection profile does not disable the TCP checks that can cause the firewall to drop packets due to asymmetric routing. It only allows the firewall to use a global timer for asymmetric path detection instead of a per-session timer.
Option C is incorrect because setting "Reject Non-syn-TCP" to Global and "Asymmetric Path" to Global in the Zone Protection profile does not disable the TCP checks that can cause the firewall to drop packets due to asymmetric routing. It only allows the firewall to use a global timer for both non-SYN TCP rejection and asymmetric path detection instead of a per-session timer.
References:
1 https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClReCAK
2 https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClSHCA0

Explanation
https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/firewall-administration/manage-firewall-administrat