No, no one can delete the output log from the Magento backend System ⟶ Command Runner by Magediary ⟶ Log until auto clean set from the backend configuration Store ⟶ Configuration ⟶ Magediary ⟶ Command Runner ⟶ Log ⟶ Auto Clean.
Yes, it can be possible by disabling answer form. To disable the answer form for the frontend, set the following configuration to No Stores > Configuration > Magediary > Product Questions > Answer > Show an Answer Form : No
Yes, we can add a list of IP addresses and/or URLs in following configurations under the Store ⟶ Configuration ⟶ Magediary ⟶ Store Maintenance Lite ⟶ Restrictions that we want to exclude. Allowed IPs Reference ...