I'd put the fan on a separate switch from the rest of the lights. Are there lights in the closet, too? I love your layout. Have you considered putting a linear drain in the shower so that you don't have the drain in the middle?

The best lighting in a bath near a mirror could be the old double swag, one on either side of the mirror somewhere out of the elbow knocking it area? LOL If you put it above your head/mirror...you get shadows. You might should look into a pair of sconces on the wall at about temple height, your temples that is..... on either side of the mirror. That would likely be best.. https://www.build.com/progress-lighting-p300084/s1426556?uid=3354999&source=gg-gba-pla_with_promotion_3354999!c1046160435!a53027215564!dc!ng&gclid=CjwKCAjw6-_eBRBXEiwA-5zHaeTUU_dOftfWPHAfO4gvU_M9b43XlNo25RrJNfMh6rT2PxyaEBsUyRoC_V0QAvD_BwE

You do not need two lights over the tub . One centered will be fine. Not sure you want to light up the toilet either. I would want the exhaust fan central in the room, its not a big room so no need to push it over the toilet. so I would go with number 1 layout but only one light in shower. do a 6'' in shower if that makes you feel better. Idk why everyone went 4" .

Before buying anything, carefully remove the fixtures to see where the electrical boxes behind them are. I assume that these fixtures are centered on the sinks and that you would want new fixtures to be installed the same way. In my bathroom, I removed the fixtures only to discover that the electrical boxes were offset because the vent pipes -- centered on the sink -- were in the way. The builders had installed wide fixtures like yours to accommodate the offsets. Replacing the old fixtures with replacements was a big hassle; I actually had to install them on the (new), tall mirrors.