Can Ripple XRP be a good store of value with >50% ownership known? The fact that the vast majority of XRP ownership is known represents from my point of view the main threat to the value of the currency and the project itself.

Do Ripple founders and OpenCoin have any strategy in case authorities confiscate their XRP funds? Government could try to do that in order to stop Ripple development as it is done at the moment.

Would they liberate the code then so the open source community can take over its development?
If the company were to cease operations or break down in some way, the code would immediately become open source. At least one developer has that clause in their contract. If something were to happen to the company's store of XRP before the network is sufficiently distributed, at worst, the ledger would be reset. (We have contingency plans that mitigate damage, but they're not pretty.)

These are risks, and they're part of the reason that getting the network distributed and the server source code open is a high priority for us. It's not just a matter of trying to do the right thing, these are threats to OpenCoin and risk is a drag on adoption. So we want them gone as much as anyone else does.

Personally, I don't think XRP is a particularly good store of value now. It's not so much the risks you mentioned, because I think they're small. It's the unpredictability of the value of XRP due to market forces, widely variable speculation, and so on.