I did figure out the multiple delete issue, when you are in the inbox, hit menu, then delete, then you will be able to X any email you want to delete, I am so glad I found this.
When in the mail app;
menu/delete/menu/mark all/delete
Once deleted they will stay in your deleted folder for the number of days you have selected in
mail app/menu/more/settings/send & Receive/download options.
If you have that for 7 days, then anything older than 7 days will be removed permanently from the phone