Just a moment, Gonzales. I meant this to be merely a shield for the Moteino to try out this exotic RTC, not as a replacement for the Moteino. So, whether your Moteino has an LDO or not is really up to whether you remove it or not. Likewise with your RFM69 choice.
The alternative, which I personally favor, is just a small breakout board that one can plug into a breadboard. Then you can wire into it however you want with whatever platform you want. It's really just a way to easily test drive the RTC chip. ie. it's a learning tool. So, I think that's what I'll make, as that way the PCB will cost less because it would be smaller than a Moteino shield, as well as taking much less time to design.
It will give some feel for whether interfacing with this RTC is a hassle or easy to do. I'd much rather have a library for it before embarking on this. There are some homemade libraries for the AB18x5 on github, but without a way to try them, it's hard to know if they're any good.