Hello!
There's a lot info in your description and some questions and I'll try to be brief hehe...
First of all, I'm a bilingual (Spanish/English) native speaker, yes... Bilingual native, this is because I was born in a bilingual environment, read my profile info, there's more about me I'm a translator.
Second, when I think about the volume of work you're talking about I imagine you may need more than just 1 person, am I right? I know (trustworthy) individuals who can help out.
Third, I have no BIG experience doing data entry but I've done it before and I'm very good and accurate when working on computers.
Forth, I usually charge per word/page when translating/typing/data-entrying... We can discuss that on chat, I'd need some further details.
Fifth, I'd like to try a sample so I can (better) see what this project involves so I can (more accurately) offer a final price/timeframe.
If I missed any question you can ask anything you want via PM
Regards