Agree about a mini waterlily! Normal ones can get HUGE! Mine takes over a third of the pond and will get bigger.
You can get "floating" plant baskets which sit on the top of the water and will float about the pond. (you can also "anchor" them to the bottom of the pond by a weight so they stay in one place) You can also get plants pockets and baskets that you can hang over the side which will save their roots being dined upon. Some places also do gravel effect pond liner strips which you could drape into the pond (all artistic like) to help pond critters in and out of the pond or get marginal draping plants that go into the water.
Best bet is to google pond suppliers for ideas and plants , you can get some gorgeous plants like reeds and other flowering plants which not only look lovely but, if you are lucky enough to get dragon and damsonflies visit your pond, means in a couple of years the nymphs will climb out and onto those to hatch out.
Are you planning to decorate round the pond with rocks? If so these will provide great hidey holes for toads and frogs.
Definitely need some snails, I have 2 large species, one ramshorn and one large pond snail which both grow huge and provide their own entertainment for you. Beware you don't need many to start with as they breed like underwater rabbits.
I currently have 3 normal fish (1 white goldfish, 1 white fantail and 1 shubumkin) plus minnows and sticklebacks (both the minnows and sticklebacks have been bonking like mad over the last 4 years so many little babies which are lovely to watch) The minnows are fascinating to watch and some of the breeding adults are huge buggers!
I was always under the impression fish only grew to the size of their environment but in our old pond (which is the same size as my current one and isn't huge) ) we started off with about 5 normal goldfish and ended up with a pond full and none were small. Some we had for about 10 years and grew HUGE (like big fatty happy fish)
1 metre deep should be ok for normal pond fish to survive the winter but if he has gone bonkers and got koi you are screwed!