Amie, first, I'm sorry to hear of your loss and hope you're doing well.
Since this is through an estate, it's a little different, all three of you take title and brother and sister sell thier 1/3 undivided interest with a warranty deed. If they will finance that, that would be best.
Your estate attorney I'd bet can do this for you. Here are some issues for all of you to address with your attorney;
1. I would have the property appraised or at least get a BPO to establish the market value, if that has not already been done by your attorney.
a. The valuation will establish a sale price for the interests sold. There may be events where your brother or sister may need to show this transaction being at arm's length and a note was made to finance the transaction.
b. Showing the valuation at market value and the cost will establish your depreciation.
2. The best way to finance it is with one deed of trust and one note. Since you have two others, doing a note and deed of trust to each means someone will get a second mortgage. One DOT puts them on equal footing.
a. People get divorced, die, become incapacitated, take bankruptcy, get sued as well as other events in life that can have an effect on thier position as a note holder, being in a first and second position can casue further problems, and in turn may cause a problem for you as well.
b. This is an equity financed obligation. In the event your brother or sister would ever have to have thier assets valued, the note will need to meet tests as to having been originated at arm's length since it is between related parties. The appraisal or BPO as well as the interests conveyed will establish the validity of the note.
c. As to the note, one note may be written with two principal parts, a principal part of the first part in the amount (of say) twenty thousand. The note is written to describe the principal amount, interest rate and payment required to each principal part. The same is done for the principal part of the second part. Then other note terms can be written as being applicable to both principal parts, for example, agreements to keep the property maintained in good condition.
d. Setting aside principal amounts to two note holders divides the total principal amount financed which is secured by the deed of trust. This also makes each note share more marketable in the event one party wanted to sell thier interest or payments under the note.
e. Having seperate principal amounts means that if one party desired a quicker payoff, for any reason, you could work out additional payments of principal to one party and not the other.
f. This split simplifies thier estate or any assignments they may do in the future if they elected to do so, like assigning the note to thier trust without encumbering the other parties interests.
g. Accounting for interest and principal reduction is accomplished with two amortizations, one to each holder. The application of payments is done on an equal basis with any odd amount being applied to either principal part. (This is necessary to disclose in the event of any loss proceeds for an insured loss or other settlement required)
3. Initially, you will have 33% equity in the property and that is more than sufficient for refinancing requirements after one year. To refinance both "partners" holding the note will agree to the payoff (as they would anyway with two seperate notes).
Since this is a small amount, about 20K to each, I'd suggest you fully amortize the loan over say 15 years, at 6% about 337 a month, with taxes and insurance, maintenance and vacancy you should get 100/150 per month, guessing, but probably. I'd suggest you offer a balloon payment in 5 to 7 years. You could do that sooner as you all may agree and one could be paid off before the other as well. Understand that your refinancing this property will likely need to be a cash out refinance as the principal owing will less than what most lenders have as thier minimum loan amounts. Probably rolling loan costs in the loan.
All of this depends on your family as well, if they will accept about $168 a month from you. You'll never know unless you ask.
If they are willing, I suggest you take the points I mentioned above to your attorney and consider the aspects I described. Good luck!