always prefer separate toilet with handbasin, the bathroom has plenty of space for generous fixtures up to the sizes shown but the bathroom should be planned to suit potential users and relative to the whole plan (where are the windows?) next door rooms, orientation, outlook etc...this is one suggestion that has the best view on entering the room with the shower (tallest) at the side, bath with potential view, vanity with option for two basins and matching mirror doored wall cabinet and the toilet handbasin next to the shower keeps the plumbing sounds away from adjoining rooms more details may inspire other suggestions

Maybe look beyond the footprint of existing bathroom. We renovated a bathroom where we were able to have a seperate large shower and keep the bath by incorporating a built in cupboard in a bedroom room adjacent to the bathroom. New Free standing storage in that room has resolved any issue with the loss of the built in.

Will need to see layout to give opinion. Doesn't look like a free standing tub is a good option for you but if you show us the layout we can give you an accurate advice.

If you can narrow the linen cupboard, then you do do a similar layout to that GB has shown but with a changed door swing, swap the basin and WC, putting the WC on the wall beside the door so the WC is concealed behind the door.