a$)$ The risk of an Information Disclosure threat in this scenario could be that an unauthorized person or entity could potentially gain access to the biometric data $($facial recognition templates$)$ and payment details stored on the remote server. This could happen through various means such as hacking, data breaches, or even internal misuse. The severity of this risk is high as it could lead to identity theft and financial loss for the customers.

To avoid this risk, the company could implement strong access controls and encryption for the stored data. This means only authorized personnel should have access to the server and the data should be encrypted both at rest and in transit. Regular security audits and vulnerability assessments should also be conducted to ensure the security measures are effective.

b$)$ The risk of a Tampering threat could be that an attacker could manipulate the biometric data or payment details stored on the server, or even the facial recognition process itself. This could lead to unauthorized transactions or false authentication. The severity of this risk is also high as it could lead to financial loss and damage to the company's reputation.

To mitigate this risk, the company could implement a secure coding practice to prevent common vulnerabilities such as SQL injection or cross$-$site scripting that could lead to data tampering. Additionally, the company could use intrusion detection systems to monitor for any suspicious activities. Regular backups of the data should also be made to ensure data integrity.