Do you have the orange or yellow in women’s size?

The wristband will easily fit wrists of approximately 11 to 21 cm circumference. For wrists outside this range, it might still fit, but feel unpractical and/or less comfortable to wear. The watch is not very big, so it looks ok an a small wrist, but it is still big enough to not look silly on a stronger wrist (20 cm circumference). On a related note, the yellow watch is not really a bright and vibrant yellow like a New York taxi, but ever so slightly more on the mustardy side of yellow. Still looks very good.

Is this a genuine Casio? Sold by Amazon, is it really fake as reviews suggest

All Casio bought from ourselves are 100% genuine with the box and guarantee direct from Casio UK, not imported or fake. My only advise would be to stay away from a watch of this type selling for around the £10.00 mark.

is it waterproof for just swimming in a shallow lake ?

I wear it in the shower, I've swam across a large lake with it on, and I wear it in the swimming pool including down to approx 6 feet deep and it works fine. I have not tried it deeper. There are other casio watches certified down to 50m which you may want to go for if depth is an issue, and these I've tested out diving and they're great.