the main thing i see you doing wrong is you started with her enclosure! you need to deal with all your other snakes BEFORE you go into the quarantined critters enclosure - cause if there is anything she can pass along to your other snakes... then this is the way to do it.

other than that. i would leave her covered if she has to stay in your living room... if you can move her to a quieter location i think that would benefit her greatly.

and in the future, when she postures or tags you... respect her feelings and get out of her enclosure. by staying there and continueing to clean you were telling her that her feelings don't matter. IMO showing her that you respect her will go a long way to assisting her to trust you.