What metrics assess the "exit feasibility" of private equity investments in frontier markets with illiquid secondary markets?

Frontier markets have low liquidity, making it hard to sell portfolio companies . PE firms typically exit via IPOs or trade sales, but these options are rare in regions like the Sahel. How do they measure exit potential upfront? Do they identify strategic local buyers (e.g., state-owned enterprises) before investing, or set minimum trading volumes for local stock exchanges as a pre-condition? I seek exit planning frameworks specific to illiquid markets, including how to structure deals for secondary sales to other private investors if public exits fail.