YIKES

I don't understand why you would have effloresence if the bathroom has been waterproofed under the tiles, the question is where is the grout drawing salt from? The silicon job isn't great, but can see how hard it would of been to do. I think you won't notice this as much as time goes by.

By using a contrasting tile in your shower niche it will draw attention to the niche and your collection of half used shampoo and conditioner bottles. By using the same colour in the niche as the surrounding wall tile will make it less of a feature. Best of luck, Dr Retro of Dr Retro House Calls

I have a shaker style kitchen and went for a combination of knobs on the doors and pull handles on the drawers and I love the end result! Id go with your last two options, I wouldnt recommend the first two handles you have as they will date more quickly than the others (and also cleaning them would be a hassel)