Hi @Mer,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
Unfortunately, due to the waterproofing requirements for bathrooms, replacing a bathtub with a shower and replacing vanities where plumbing is present are not a simple case of pulling one out and putting the other one in. More often than not, it means stripping the bathroom back to a bare shell, reapplying the waterproofing membrane and then reinstalling everything.
I can certainly give you an idea of the cost for specific products, but you'd need to get someone in to quote on a bathroom renovation to really get a good idea of the cost. This is not something I am able to provide an approximate price for.
Depending on the size of the shower, prices for shower screens vary from around $200 at the low end up to $2000 on the higher end. Have a look at shower screens for an idea of price.
Again, wall hung vanities start at around $200 for simple things and can go up to some pretty high prices, in the 5-10k mark for bespoke joinery.
When you say mirrored vanity, I think you mean something like a shaving cabinet. These start at around $50 on the low end and can go up to around $1500.
Ultimately, you can price up the pieces you are after, but the tough variable to price is the labour to install them. If you select the items you want and go to a bathroom renovator for a quote to install them, this will give you the best idea of what it will cost overall.
You might like to have a look at How To Plan a Bathroom Renovation for some further guidance.
Jacob
