I'd agree with Arrowhead on the bridge issue. The Macau, Guangdong and Hong Kong authorities have to reach consensus on all of the immigration, construction and funding arrangements. Lots of egos to placate and pork barrel funds to allocate, so this is not going to happen fast.
On Viva, well Arrowhead the jury is out. If Venetian decides to buy them purely for an AOC, they will presumably only want to pay up to what they calculate it costs to push for a standalone AOC themselves (and this already assumes that they can cut through the regulatory mess linked to buying a sub-concession from Viva).
This would mean that the Viva investors (who must be in for a lot more than the AOC set up costs alone as they must have been operating at a significant loss this year) would not get anything close to their original equity investment back.
I suppose they could accept a fire sale if they decided that this was the only way to cover some of their losses. The irony is that they can't argue that the sub-concession is worth much as part of any rescue deal as Viva is insisting that it needs to fly to points outside of it to survive! Its tough to cite the subcon as a legal asset worth paying for when they seem to regard it as a commercial liability....
On the business model, your logic of charter operations being 'all paid for' only extends so far. Sure, the risk passes to the charterer for the duration of the charter contract but if he discovers he is losing money himself he just won't renew the deal. Assuming he is signing short term contracts, this doesn't give Viva much breathing space.
So, what are the economics behind the charterer's business? If - as you point out - the fares being advertised are not much cheaper than CX or QF flights from Sydney, we return to the original question of why people would choose Viva. Will they regard the 90 minutes less land travel time from HKG as more valuable than the loss of the benefits of full service carrier product highlighted previously?
I doubt it. The only reason for large numbers of passengers to shift to SYDMFM are a clear and sustainable cost saving to the customer from choosing to fly Viva to Macau. But the costs that you cite as providing an advantage (airport fees, some lower expenses for ground staff) are too small a percentage of the overall cost base to allow for significant fare differentials to be sustained.
One final comment - I hadn't heard that they were trying to wet lease one of their aircraft. If so, it seems inconsistent that they effectively halve their fleet whilst talking about the exciting opportunities in Macau for low fare airlines. If they had a genuine cost advantage, surely they would be keen to maximise it by spreading their lower cost base over a larger operation to as many passengers as possible?
My guess is - if I understand you right that they are trying to wet lease - that this is more a sign that the business model is heavily under water for the foreseeable future, and the only fallback is to try to conserve cash whilst they hope for a change in the aeropolitics. This may come sooner rather than later as NX doesn't exactly have a reservoir of goodwill to fall back on locally. The question is how long this takes and who they can find to fund the wait.