Is it possible to know the company's net income without the preparation of the income statement? If yes, how

P&L is an essential report. However ,, Indirectly you can figure it out, by the preparation of the Cash flow statement (By Analysing the increase and decrease of the Assets, liabilities and equities )

Yes and simply ask the net assets of an entity end of the period (property rights) of the net assets of an entity beginning of the period, taking into account the launch of any new investments for the owners of property rights, but it does not substitute for the work of the income statement