Well first I was married to Ysolda. I killed her and when she died I got a letter of inheritance but with the wrong name...? Then after getting the jagged crown and reporting to Ulfric another letter came when I was outside. this time the person was someone I never heard of and isn't even on the marriage list. What is going on? Please explain if you can.

If a named npc dies and their relationship with you is good you will reveive an inheritance upon their death. It was probably a random npc you did a quest for at some point.