You can use Product Add Ons plugin for WooCommerce.http://www.woothemes.com/products/product-add-ons/
When talking about hosting, it is all about server resource usage, For example, when using Cpanel-based shared hosting, you can see CPU usage in your control panel. Every shared hosting has different limit for CPU usage, your website will be suspended if it reach the limit, and usually your hosting will give you some notification with some options. Some of shared hosting also give you a limit to the disk space and bandwidth.
High traffics also increase the server resource usage especially when you use dynamic website using PHP. Google Analytic is enough, but you can always try to use other tracking stat, for example HiStats, Jetpack Stat, etc.
Then, you can also start optimizing your website using some caching plugin (for wordpress there are W3 Total Cache and Super Cache) to reduce the server resource usage.
It is recommended by Google, so it worth to try…
Btw, have you tried WPML plugin? It works perfect for your scenario. The main website (root) will use English, and you will get /es in your Spanish post…
It depends on how many products that you sell and the traffics on your online shop. You can start using any shared hosting package. Once you increase the number of your products or the traffic of your website is high, you can upgrade your hosting package. And if it is success and get bigger, you can start using VPS hosting package. Bigger and bigger, then it is time to use dedicated server.
WooCommerce 2.0 just released last week. I believe that most of WooCommerce theme authors are working on their themes to make it compatible with WooCommerce 2.0. It is better if you can ask the author directly.
You can follow the solution here,http://wordpress.stackexchange.com/questions/4931/quick-edit-update-clears-out-my-custom-meta-values
For SEO purpose, you can use multilingual content markup. You can read Google explanation here,http://googlewebmastercentral.blogspot.com/2011/12/new-markup-for-multilingual-content.html
The most important thing for starting a partnership on Themeforest:
DON’T FORGET to make a written LEGAL AGREEMENT between you and your partner to split the profit!
It is really important because Envato will send the money to you or your partner, and then you or your partner need to send the profit share to other. We hope that Envato can split the earning automatically, but we have to wait Envanto built this feature for years.
We can keep arguing that nice design is the most important thing (in theme designer standpoint) or good code is the most important thing (in theme developer standpoint). But, once you agree to split the profit, you have to send the money to your partner, whatever happens to your partner, as long as you still use your partner’s design or code in a ThemeForest product!
When we are talking about SEO , this periodic table is worth to check http://searchengineland.com/seotable
You can see that there are many factors of SEO , but we can split them to On Page SEO and Off Page SEO .
We can’t provide all SEO factors from a Wordpress Theme, it will not be enough.
Our job (theme developer) is creating a good start for our theme user to get better SEO . That is what we call SEO Friendly Wordpress Theme.
What You Can Do To Create SEO Friendly Wordpress Theme
[ONPAGE SEO – Ac] Main Content should be indexed first before the sidebars, and don’t add too many content to your header.
It is really important when you create “sidebar – content” layout or “sidebar – content – sidebar” layout. Your content should be called first before your sidebars in the HTML code.
[ONPAGE SEO – As] Speed Optimization
Your theme should be fast enough. And your theme should support any Cache / Minify plugin to make it faster.
[ONPAGE SEO – Au] Good Permalink Structure
Encourage your theme users to use the best Custom Permalink Structure for better SEO . Don’t forget to put this information in your theme documentation
[ONPAGE SEO – Ht] Good HTML title tags.
You can add simple Wordpress filter to make your HTML title tags SEO Friendly. It is useful for newbie, when they know nothing about SEO .
You can also add additional settings to control HTML title tags. But, you can also direct your theme users to use Yoast WP SEO , All In One SEO , and others for advanced HTML title tags control
[ONPAGE SEO – Ht] Meta Description Tag Control.
It is useful to control the appearance of your search engine result. You can also add additional settings to control meta description tags. But, you can also direct your theme users to use Yoast WP SEO , All In One SEO , and others for advanced meta description tags control
[ONPAGE SEO – Hh] Proper h1/h2 placement.
When in homepage / archive page, you should use H1 for your website title, and H2 for others.
When in single post/page, you should use H1 for your single post/page title, and H2 for others.
[ONPAGE SEO ] Inner Linking
Adding related posts / related products feature is also important for inner linking.
[OFFPAGE SEO – Ss] Social Media
Social networks has good SEO impact when we use it properly. Your theme should have Share This (FB/Twitter/G+) feature.
So, that’s our job as a WP Theme Developer. The rest is our theme users job, how they create high quality content, how they create a good online reputation, how they create a good online authority, and how they manage their backlinks.