From what we know about this woman, I would say she was methodical, meticulous, and cared very much about her appearance, but not to the extent that she would give up wearing comfortable clothing.
Velour was quite popular in the plus size shops, and most often used in casual sporting wear for a dressier than gym clothing look, but with the comfort of sweats. It can be made from cotton or polyester according to Wikipedia. Neither of those fabrics lend themselves to keeping a person warm in cold weather.
The iron suggests two things to me. Either she was traveling or she was obsessive compulsive about wrinkles in her clothing, and likely obsessive about other things.
I would expect to find her working in accounting or some other very detail oriented job, but not in a front office capacity in say, the financial district in New York. Her clothing does not speak to front office apparel or to working in a place where a company is trying to impress its clients.
Had she been from NY wouldn't her accent have been noticed in Seattle? No mention was made of an accent if IIRC.
If this woman had no close relatives or friends, was single, had lost her job, she might not have been missed by anyone, sadly.
On the subject of suicide, I have some experience since that's how my late husband died. People who commit suicide in the home usually have some resentment or grudge against the marriage partner or person they were living with. OTOH those who leave home to die, do so wanting to spare the person they lived with in the twisted thinking of a suicidal person. My husband left home.
This leads me to consider that she did leave someone who cared behind or else she was such a hermit, she was afraid no one would find her for a long time if she died in her own home so she chose a hotel, knowing when she didn't check out in the usual manner, she would be discovered quickly. Even in death, she was concerned about her appearance. The fact that she left a note stating that
"it's no one's fault," tells me there was an important someone or important others in her life.
Not all people who commit suicide are depressed. Sometimes it's an easy way out of a life situation they simply just don't want to face. It's the 9th. leading cause of death in the US.