A local garden store or designer will certainly be able to help you. In the meantime, you can look up ideas online, but you'll need to know some basic information before anyone can help you choose specific plants. The first and most important is to know your planting zone, which is all about your location and climate. You also need to know the directional orientation of your house and the wall, and whether it is "full sun", "partial sun", or "shade". Will you be planting on both sides of the wall? You may wind up with vastly different plants if one side gets full sun and the other is in the shade. Take into consideration whatever shade is cast by the large tree, and the house itself. If you have the time, spend a day taking pictures of both sides of the wall - maybe once an hour (shadows will shift somewhat throughout the season), so you may want to do this every few weeks and keep a visual log of how the shadows move. Also, before you plant, decide if you want to paint the wall. It will be easier to paint before you plant, of course. White will reflect heat back onto plants. Climbing plants would look nice on the wall, if you're not going with a very structured garden. Ivy is an obvious choice, but there are other vines that flower beautifully, if you like that idea.

Looks like the palm tree look is working so I would blend that with some succulents maybe agave which can grow large and make great statement plants. Also stick with the stones.

I would consider a small retaining wall perhaps 2-3 planks high this will provide support to the bank but also allow the pathway to remain clear and formal. The ferns seem to be doing well but could do with a tidy up. I would also prune the tree so it allows a bit more light into the section to help prevent dampness, you also want to take it away from the house, without destroying it's natural shape. As ferns seem to naturally want to grow there, you could continue that theme. Perhaps some other shade / cooler temperature type plants with some flowers could be a good addition. I am not sure which plants can tolerate the cold Dunedin winters, so you best contact is your local garden centre. You want plants that are lush all year round. Also have a look at other plants growing in the neighbourhood as that will give you a good idea of what does and doesn't do well in your climate. Good Luck.

I have not heard anything bad about having doors that open from any direction of the house and as you have not confirmed which country you live in I can not even predict where the worst of the winds would come from. I live in NZ and my front door faces North West. Where I live that is the worst / strongest winds that we have so the only negative for me is on a story day I might be blown down the steps or the rain might soak me as I try to unlock the door. I have simply eliminated what I can by adding a glass roof above my front deck. My back door faces south east and again the weather was and is the only problem so I enclosed this area with a porch which allows me to have the door open most days, almost all year round. NZ's bad weather comes from the south and the sun is in the North. If you are also in a similar location / southern hemisphere then your plan shows me your house is perfectly positioned for the best of the sun. I think you have absolutely nothing to worry about. Don't listen to negative comments make the most of what you have and if you need to make small adjustments for wind, rain or too much sun. ENJOY YOURSELF AND YOUR NEW HOME.