Given the time constraint and the need for specialized knowledge in financial markets, inviting a guest auditor from one of the organization's affiliates who has the required expertise is the most appropriate solution. This approach leverages existing internal resources with the necessary skills, which can be more efficient and cost- effective than hiring new staff or outsourcing the engagement. Additionally, it facilitates knowledge sharing and can help build internal audit capacity for future engagements.
:
The Institute of Internal Auditors (IIA) - Standards for the Professional Practice of Internal Auditing, Standard
1210 - Proficiency

To determine whether company vehicles are being used for personal purposes, the auditor needs location and route data of the vehicles in addition to the initial data extracted. This additional information would allow the auditor to track the specific routes and destinations of the vehicles, making it possible to identify patterns of use that do not align with business purposes, especially during weekends. The location and route data can help in pinpointing any non-business-related usage of the vehicles, providing evidence of personal use.
:
IIA Practice Guide: "Auditing Operational Activities"
COSO Internal Control - Integrated Framework

An internal control questionnaire is most appropriate in situations where controls need to be assessed across decentralized offices. This tool helps gather consistent information on the presence and effectiveness of controls in multiple locations, ensuring a standardized approach to control assessment. It allows for efficient data collection and comparison, which is critical in decentralized environments where processes and controls may vary. References: IIA Practice Guide - Evaluating Internal Controls, IIA Standard 2130 - Control

According to IIA guidance, the chief audit executive (CAE) is directly responsible for establishing the objectives, scope, and plan for each engagement. This responsibility ensures that each audit is properly focused and aligned with the overall goals and risk areas of the organization. While maintaining a quality assurance program and providing professional development opportunities are important, they are not solely the CAE's responsibility without management support. Periodic review and approval of the internal audit charter is typically a joint responsibility with senior management and the board. References:
* The IIA's International Standards for the Professional Practice of Internal Auditing (Standards), Standard 2010 - Planning.
* The IIA's Practice Guide on Developing the Internal Audit Plan.

An internal control questionnaire (ICQ) is designed to gather detailed information about the operation of specific controls within an organization. It is particularly useful for understanding whether controls, such as adherence to approval matrices, are being followed consistently across different units. ICQs provide a structured way to collect this information from respondents, ensuring that all relevant aspects of the control environment are considered. This method is effective for assessing compliance with established procedures and identifying areas for improvement.
:
Institute of Internal Auditors (IIA), Practice Guide - Internal Control Questionnaire.