I think she fancies him, and it's possible that she might be trying to get him. I don't say it to make you anxious, but just to say, beware. You've given a lot of examples, and they are all about physical appearance, or getting physically close.
When there was newspaper reporting about the security guard who left his wife to run off with the Ukrainian woman, I read the comments beneath the articles, and posters were saying that in some parts of the world, women see it as important to get a man, and some are unscrupulous. This is a terrible generalisation, and not all are like that, but you seem to be minimising a lot of obvious signs. I also think it true that an older handsome man with a good job, and able to afford a lovely home, might seem like a good proposition, as another poster has said.
I think it's possible that this lady is making a play, while she has the opportunity, and hoping that your husband will keep in touch with her, after she has gone back. I also think that your OH.might have got used to the attention and might miss it and might be tempted to keep in touch, telling himself that he will keep it innocent.
If she does all this coaxing when you are there, what does she do when you don't have sight of them?
I think the best thing you can do is to speak sternly to her. Tell her you've noticed she is giving your husband the eye, and you've seen her trying to get him to sit by her/ give her a lift and you're warning her now to stop it. Say it's inappropriate behaviour. Say you don't want her wearing scanty clothes in your home and you're prepared to tell the person who's invited her over here for work to be careful of offering her opportunities like this again, because she is a disruptive presence, and some couples might be made unhappy by her behaviour. You can say that if she says she is blowing up nothing out of proportion, then fine, you stand corrected, but please can she be more careful and wear suitable clothing. I don't see her telling your husband, and if she does say something, you can tell him you feel you're entitled to tell her you're upset.