You are going at the perfect time! Hobart experiences one of the best weeks of the year from Christmas to New Years when we celebrate the Hobart Summer Festival. The whole waterfront is packed with entertainers, stalls and people! The main reason being the Taste of Tasmania festival which is held in one of the shipping warehouses near Salamance Market. The Taste of Tasmania is amazing and is literally a market of all the best restaurants and produce we have to offer. Each stall only serves sample size plates so you can enjoy a whole range of amazing little meals! There will be buskers, bands and performers there as well. I would recommend this as my number one things to do in Hobart. If you do decide to do a tour, just make sure it is a half day so you have plenty of time to wander Salamanca and the Taste and really enjoy the atmosphere of the wharf.
Clothes-wise, please break the news to your husband gently! But remember you can also get some lovely clothes here in Aus, though a lot more expensive than the US.
Have a fantastic cruise!