1) Add the elggdata folder to data.zip BUT delete all files of root folders of that elggdata
2) Take the data.zip after logging in the manual installation.
3) At the moment there is no upgrade to 1.12.x to 2.x
4) Add a trailing slash '/' for datadir path in manual installation. (Not required since 2.1.2)
5) Timezone = America/New_York
6) We have disabled auto upgrade since version 2.3.0 (since it requires logging in to upgrade the database , to make changes to database schema).
7) PHP REQUIREMENT LINK: http://learn.elgg.org/en/2.3/intro/install.html#requirements