Wow I'm so jealous! A new garden! We are waiting to sell our house so I can't really do anything in the garden at the moment apart from keep it 'tidy'.
sniff
Stuff in pots is always good - you can move them around, change them, have colour through the year while you discover the exciting things in your garden. You can always plant the stuff out in the garden later
I would also second the caution about E. canadensis (its listed as an invasive plant) therefore I would avoid if possible. I'd also recommend 'No Nettles Required' although I'm still tempted to have a big patch of them in full sun.
You can always feed the birds to bring some life into your new garden - make sure you do it regurlarly with good quality foods. (Although a word of warning - I found it can be quite expensive).
So much good luck to you in your new garden!
Oh, you can also have a 'tub' pond. I have one of those (I'm not allowed a real pond as the neighbours kids might fall in....hmmm). I have a small water lily in it which flowers from mid summer to early autumn. Plus the birds can drink out of it too. Theres some ramshorn snails in it, a leech or 2 (ewww) and some sort of daphne things.... I don't think its big enough for surface whizee things but its a temporary arrangement!