The current high capacity NiMh rechargables are pretty good for digital cameras. There is a relatively high initial outlay, but in the long run much cheaper than alkalines. With the 2500-2700mAh cells they really last a long time per charge.
Many of the compacts digitals have proprietary...
I'd have some concerns about flowability of the 15W-40. Especially in the cooler weather. The 0W spec is there for a reason and I believe it has to due with faster lube on startup, and possibly some to do with fuel economy.