Equity and Net Income is the same under Equity and Proportionate Consolidation. ROE is the same. ROA is higher, leverage is lower, profit margin is higher under equity vs proportionate consolidation.
Net Income is the same under Equity and Acquisition Method. Shareholder’s equity is not the same however. Again. ROA is higher, leverage is lower, profit margin is higher and ROE is higher too under Equity method.
Less than 20% is passive investments, 20-50% is equity method and more than 50% is acquisition method.
For JV, US GAAP allows Equity method and IFRS allows Proportionate Consolidation Method.
Pooling of interest (discontinued) - but you take book values of all assets and liabilities.
Operating Income will be different under Equity and Proportionate C and also between Equity and Acquisition Method.
Please correct me if I am wrong and feel free to add more.
Proportionate consolidation is still allowed under IFRS. This is where you take the pro-rata share of the subsidiary’s B/S, I/S and include it in the original company’s B/S, I/S.
For #3 you also have to look for info about significant influence and control, which is the key determining factor. I could see them saying they hold an 18% stake, but have significant influence.