Girls in stores - BUT not cold (is previous)

I've read the 'girls who work in stores' thread, this is a little different because I know the girls from outside the stores and bumped into them working there by chance. Could be a tricky one so for the record what is advised in these situations.

For me personally the sits are:
1) local pharmacy / sort of know her from elsewhere
For the purposes of trying to describe the level of 'knowing'/acquaintanceship
This girl used to commute with me quite often. She was good looking but I never took to her until I heard her for the first time, she's foreign and it just intrigued me.
(legitimately couldn't strike fast but not for the first time it took a while for me to become interested for me, also triggered by the possibility they're interested)
I wanted to approach somehow, not sure its not platonic (all the same cons present), from then but never got around to it for the usual AA reasons and my specific situation described in my intro (no idea where stand formerly self-con to BDD and then start getting good attention from girls)
(*how do you approach a girl, with platonic intentions?)
First unboarding, nobody was left but me and her it, she had a good look just before and as I passed her I know its virtually nothing but its still not something that happens universally (and its happened a few times recently with others, can't say I notice this happening with guys). As explained in my intro, there's a heightened awareness of these things good, bad or nothing because of the good that's happened.
Next, after looking up from my phone then out the window on another commute, she was sitting at the front, and I just happened to turn that way and 'caught' her looking, she, usually cool customer, quickly turned away. I've read enough to know that this is often given as a positive and I took it as such but know it could just as easily be nothing or with me bad.
Soon after cueing she sat next to me, fair enough, I was the next in line but taking the positives out of it at least she's not uncomfortable, which is always a concern. I just plain bottled opening because of the confusion I'm in and hence why have had to ask for help. I knew that I couldn't not open her one way or the other next time, so only made the commute when I was feeling confident but never saw her on it again.

As an example of what stalled me at times: I saw her pouting in the window, applying her make-up and she just looked gorgeous she must be taken and obviously aware of her prettiness through that prism there its puts a different slant on catching her looking, if taken and/or not interested.

By chance I happened across her place of work once. Knowing she works there I've been thinking about enquiring about her with someone on the till *would like thoughts on whether this is acceptable and/or what else I can do about this.
But recently I've twice walked past her in the mall, wasn't expecting it of course on either occasion and at first wasn't sure it was her having not seen her for a while but most recently we passed near where she works (I thought she'd left). It was only a few seconds but one of those where you both realise something, think you recognise or are not sure whether to say hi or something. She looked kinda scared if I were to describe it, starring ahead, eyes open aware.
I mood swing from thinking about just going in there and dealing with it asking about her and if they'd pass a note on - straight and up-front then thinking is that weird/wrong? (also Xmas is coming - Xmas card perhaps)

2) Jewellers - virtual strangers in this case (nearly, if not, cold)
Had an incident passing a store that was shutting down, staff outside locking up. Caught eyes with a gorgeous girl that works there out of the blue when passing as they were closing and had that eye-contact, look away, look back, are they still looking, catch each other thing happened three times as I passed. This was unplanned, unexpected so just natural.
I wouldn't think anything of it as she's top rank before the good and possibly good attention of relatively recent times (not consummated) which has me thinking there's a shot and that there could be something good in any given (not all) such incident.

whats the recommendation in such situations?