I'm so jealous. It's perfect for a heavily planted tank with a large school of harlequin rasboras, cories, a nice pleco and rainbows.
All you need is the filter to get started now. A work in progress is always more fun anyway. Start planting the back and little by little work towards the front. No need to cycle this one. Just plant it, add some filter media from the other tanks, a heater and you're good to go. You'll have it done before you know it. Sometimes you can find people who give away their plant trimmings too rather than throw them out.
Whatever you decide have fun with it and post pics as you go along. You're so lucky.