Keeping WP database synced across multiple developers using git

I’m working on improving my git workflow as it applies to my WordPress development projects. Often, when developing a content management system, I’ll create a development server (like http://dev.finalsitename.com) containing the custom post types and taxonomies that will be used in the production version. This allows my client to begin adding their content to the site.

When is it appropriate to create a new table in the WordPress database?

For a client we’ll need 29,000 terms (all the highschool’s in the US) and each term needs 6 meta items (address, phone…). My initial thought was to store the term meta information as suggested in this post but after looking through it again I will be using lots of terms and I wonder if it will overload the options table.

Multiple WP install with same users database

I am creating a e-commerce website. I am using woocommerce with some cool extensions I bought. I need to make 2 websites, but store the users database (purchases, subscription purchases, etc) as well as products in a single database. The rest of the content should be different (pages, posts etc) so the administrator can see purchases from site1 and site2 while logging in to the one site. Is this possible? Sorry for my bad english.