I have 2 questions regarding K1.
Yes, if you expect to receive Schedule K-1 from your investment late in the year, you may file your return before the April deadline and amend it when the K-1 arrives. Your other option is to request an extension of time to file (due April 15), which gives you another six months to complete and file your return.
The management fee is an investment expense rather than an adjustment to your basis in the partnership. Investment expenses are a miscellaneous itemized deduction. This means they are deductible only if and to the extent they, along with your other miscellaneous deductions (if any), exceed 2% of your adjusted gross income.
If the management fee is reported on Schedule K-1 (highly unlikely), then you would not need to record this expense. Any reduction in your basis would be included in the allocated income/loss on the K-1.