Comprehensive and Detailed In-Depth Explanation:
The definition provided in the question matches the APMG Change Management Foundation's description of Engagement, which is the process of involving employees and stakeholders in change initiatives to build commitment and ownership. Engagement is a deliberate strategy to enhance participation and support, distinguishing it from roles like Change Agent (an individual facilitating change), Sponsor (a senior leader championing change), or Line Leader (a manager implementing change locally). The focus on "increasing involvement" aligns directly with Engagement as a foundational concept in stakeholder management.

Explanation
Two-way communication is a type of communication that allows for feedback, interaction, and dialogue between the sender and the receiver. Two-way communication is useful for engaging stakeholders, building trust and rapport, clarifying expectations, and resolving issues. Two-way communication encourages and increases people's motivation to interact to find out more, as they feel valued and involved in the change.
Therefore, statement 2 is true. However, two-way communication is not useful for getting important information out quickly to large groups of people, as it can be time-consuming, complex, and inconsistent. For this purpose, one-way communication, such as newsletters, emails, or announcements, may be more suitable.
Therefore, statement 1 is not true. References:
https://apmg-international.com/sites/default/files/Change%20Management%20Foundation%20Sample%20Paper (page 11)

Mayfield's stakeholder radar technique identifies four levels of engagement for stakeholders: required, desired, actual, and planned. The required level of engagement is the minimum level that is necessary for the stakeholder to support the change or at least not resist it.References: https://apmg-international.com/sites
/default/files/Change%20Management%20Foundation%20Sample%20Paper%202%20-%20v1.0.pdf (page
11)

Change agent networks are groups of people who act as advocates, champions, or ambassadors for a change within an organization. They can help to communicate, implement, and sustain the change at different levels and locations. One of the benefits of using change agent networks is that they help people keep up to date and involved in the change, as they provide information, feedback, support, and guidance throughout the change process. The other options are not benefits of using change agent networks, as they either imply different roles or responsibilities for the change agent networks or are not relevant to their function.References: https://apmg- international.com/sites/default/files/Change%20Management%20Foundation%20Sample%20Paper%2029%
20-%20v1.0.pdf (page 11)

Tuckman's five phases of team development are a model that describes how teams evolve and mature over time. The five phases are: forming, storming, norming, performing, and adjourning. In practice, teams may not follow these phases in a linear or sequential way, but may go backwards or oscillate between the stages depending on various factors, such as changes in goals, leadership, membership, or context. Therefore, team leaders and members need to be aware of the current stage of their team and adapt their behaviors and actions accordingly.