I recently finished a remodel and have a hand held shower head as well as a fixed shower head.

The extra hole is irrelevant IMO since you are doing a gut remodel anyway. There are additional costs in terms of purchasing the fixture but the extra costs for the plumbing to add the fixture really weren't significant in terms of the total cost.

You would actually need a three way diverter for your set up if you go that route - again, not a huge deal.

At first I thought I wanted a shower head inclusive of the hand held but when I considered my options they were fairly limited if I wanted a good shower head - i.e. metal and not plastic - because a good sized shower head would have been heavy so I them decided to have separate shower head and hand held unit. The hand held unit is a wand style which is sleek and light weight but works quite well as I use it to rinse my hair of shampoo - the true test.

You should place the hand held wherever it is most comfortable for you.

I actually have two hand held shower heads as I have a bench and installed a second hand held shower head by the bench so that I can use it while sitting. That hand held shower head is installed fairly low so that I can reach it comfortably while sitting.

You should also consider whether you opt for a thermostatic valve or a pressure balance valve. The advantage for a thermostatic valve is that it once you set the temperature you like, it can remain set because there is a separate valve which controls the temperature and valves which turn the fixtures on/off and select which you are using.

In my set up I have two "valves" - one is for temperature and the other controls the diverter - 3 PM turns the hand held one - noon - turns the overhead shower head and 9 PM controls the second shower head.

There shouldn't be issues with the tiles. I actually have two grab bars in my shower as well as a corner basket. Fixtures intended for showers don't cause any problems. It was all well coordinated between the tile guy; the GC and the plumber.