My recommendation would be the same as Linus'. The Washington State Housing Finance Commission's State Bond program has been the only program that I have had clients use to still obtain 100% financing today. You will be required to participate in a day long Homebuyer class and receive a certificate in order to qualify for the program - a small price to pay for being able to receive funding for the downpayment. Since I have been certified to teach the classes for the WSHFC, I have not seen any programs specific to to single parents but rather you will qualify based on your income level, geographic area, current home ownership status, ect.,.
The loan officer my clients have been using to get the downpayment assistance through the WSHFC is Scott Estes with Cobalt Mortgage. 425-891-8260. He is also certified with the WSHFC and can direct you through the process. It's a very complicated process for the loan officer so you have to make sure you use a loan officer who is not only certified, but truly has experience with the program. This is who I would recommend.
ps- I like that you're buying in Tukwila. I think the area is under -appreciated and here are some amazing little neighborhoods in that area. In fact I just had a client buy a mini farm in Tukwila! Who knew? !