What are the main selection criteria NGOs consider when selecting suppliers?How do NGOs implement related decisions?

The research topic is about procurement in NGOs operating in these post-conflicted areas, particularly finding out how procurement is according to theories, compare the findings to
what is implemented in practice, and try to find ways to improve the existing procedures. Therefore, the way forward is to find gaps in the existing literature, elaborate a set of questions around those gaps, conduct interviews of NGOs if post-conflict area (Gaza, as an example), analyse the findings and propose, either a framework or a set of processes that
would improve the existing procurement procedures for those NGOs.
This order is about finding gaps in existing literature, which is the first step (as explained earlier). This order is also an extension of the previous one #855702. Its aim is to briefly analyse various references in relation to the following questions:
Q1: Do NGOs have a set of processes for selecting suppliers?
Q2: Do NGOs consider the elaboration of selection criteria when selecting suppliers?
Q3: What are the main selection criteria NGOs consider when selecting suppliers?
Q4: How do NGOs make decisions concerning procurement?
Q5: How do NGOs implement related decisions?
Please analyse at least 15 references per questions,  fill a table containing the following:
Reference
Related question number
Used Methodology
Research Findings
Implications and Consequences of Research
Existing Research Gap