With my dad's estate, we had his accountant hired to help out. Hadn't realized it at the time but he specialized in estates/taxes, so was very helpful and streamlined the entire process.
When my maternal grandmother died, my mom was the executrix and hired both an estate attorney an a professional mediator to sit with some of the family members that were attempting to derail property distribution and made sure things were fairly divided. It was such a mess with nasty relatives causing trouble. The lawyer was the same that grandmother used for her will, extremely well-respected in her town, and they hired the mediator for my mom.
I absolutely would recommend hiring a professional (attorney/accountant/whatever needed) if you can do so. Dealing with death/loss is hard enough without adding a messy estate to settle. This is both a relief to have someone else to handle things for you and know they'll handle them correctly, and also a protection from legal challenges now and down the road.
I am very sorry for your loss.