Junior team members can play supportive roles in negotiations, such as taking notes and observing the proceedings. These roles allow them to learn and contribute without leading the negotiation. Serving as an expert or chair would typically require more experience and authority.
Reference: L4M5 Commercial Negotiation 2nd edition (CORE), Section 3.1 - Planning and Preparation for Negotiation

According to Paul Steele's 'The Seller's Perspective', customer can be classified into 4 categories as below:
In this scenario, although SBL's spend claims large portion in suppliers' revenues, their draconian treatment will reduce SBL's attractiveness in supplier's perspective. SBL falls into Exploit quadrant. With exploitable customers, suppliers tend to 'milk' the customer and charge a high price to compensate for all the pain customer put on them.

The question asks about negotiation techniques which are not present in the book. In this question, there are only 3 recognised techniques:
- Framing and reframing: A frame is an assumption, or set of assumptions, that guides our attention and behavior. Reframing is the ability to identify and significantly change assumptions or perspectives. Framing has a significant impact on the effectiveness of negotiation outcomes and negotiator working relationships.
You can read more on framing and reframing here.
- Anchoring: Anchoring bias is well-known cognitive bias in negotiation and in other contexts. The anchoring bias describes the common tendency to give too much weight to the first number put forth in a discussion and then inadequately adjust from that starting point, or the "anchor." We even fixate on anchors when we know they are irrelevant to the discussion at hand. You can read more on anchoring here.
- Pacing and leading: Pacing and leading is a two-step lever of persuasion. First - You "match your pace" to the person you want to influence in as many ways as possible. You can do this by mimicking the way the person talks, stands, their appearance, etc. You can also mimic less tangible aspects like the way they act, or their emotional state. Second - Once you've set your pace with someone, lead them to whatever decision or behavior you want them to take! You can read more on pacing and leading here.
Reference: CIPS study guide page 163-165
LO 3, AC 3.2

Integrative negotiation focuses on collaboration, transparency, and the pursuit of shared benefits. It emphasizes mutual problem-solving and long-term value creation rather than short-term wins.
Reference: L4M5 Commercial Negotiation 2nd edition (CORE), Section 1.1 - Integrative Negotiation Approach

Mark-up % = Profit ÷ Cost × 100. Here, profit is $80, cost is $160. So, (80 ÷ 160) × 100 = 50%. This differs from margin, which is profit ÷ selling price. Mark-up analysis helps buyers understand supplier pricing structures, detect hidden margins, and strengthen negotiation. By knowing whether a supplier is working with high or low mark-up levels, buyers can challenge prices more effectively or justify alternative offers. This analytical preparation supports objective negotiation rather than reliance on supplier claims.
Reference: CIPS L4M5 (2nd ed.), LO 2.2 - Understanding costing (mark-up vs margin) in negotiation prep.