My allocated activations is still reflecting 10.
That's how many activations you've used. If you're on the Solo plan then you can use 290 more.
Can I delete these licenses and will that adjust my allocated amount of licenses?
Yes. When you delete a product key it will reduce the allocated activations (used activations) by that amount.
If I add license fields to my licenses, such as CompanyName, will this ever be added to the advanced search options.
Soon. You can already do searches by custom license fields using the web API (see: http://wyday.com/limelm/help/api/limelm.pkey.advancedSearch/). We're adding this ability to the LimeLM user interface soon.
My fear is that if I have 400 licenses activated and the customer forgets their email or doesn't know which one was used, I may not be able locate their license. Any suggestions?
Right now you can use the web API. Soon you'll be able to do either the web API or from LimeLM's advanced search page.