The deed from the executor to the sibling can then be recorded. Up to that point the property is in the name of the deceased (his estate).
Second, buying out the other siblings does not have to be in cash. The executor can help negotiate the terms of the division, including 2 separate mortgage loans against the property. The receiving sibling takes the title and the other 2 get mortgagee papers for the amount they did not receive in cash. For example, the house is valued at $300k. The receiving sibling takes title and pays $10k each to the other 2 siblings. The remaining $90k each is documented as a lien (mortgage loan) against the property in favor of each of the remaining siblings. The lien might state $10k per year to be paid for 9 years.
You do need to consult your tax advisor about receiving interest if such a provision is included, besides the whole inheritance tax issue.
Restrictions on disposition of real property are common. They will remain in force until they can no longer be followed or become illegal. For example, if all heirs die, what happens? The legacy may be lost to complete strangers, if the restriction is not thought out completely. If the living person specifies passing only to a married man and woman, but later a court rules that females can marry legally, then the restriction may be overridden by court to include homosexual couples.
Best advice -- ask an attorney.