Oracle Apps (E-Business Suite) current release (as of Sep 2015) is Oracle E-Business suite is 12.2.4 also commonly known as R12.2 . WebLogic Server is introduced in Oracle E-Business Suite as part of 12.2 version .
Oracle HTTP Server (OHS) is part of Oracle Web Tier (other components in Web Tier are Oracle Traffic Director OTD and Oracle WebCache). OHS is a recommend component as per Oracle Reference Architecture (some of we call it Oracle Enterprise Deployment).
OHS is mandatory if you wish to integrate any Oracle Fusion Middleware product (like WebCenter Portal, SOA, OBIEE, etc) with Oracle Access Manager (OAM) for Single Sign-On (SSO).
On September 1st, Oracle discontinued Oracle Standard Edition (Oracle SE) and Oracle Standard Edition One (Oracle SE1) and replaced them with Oracle Standard Edition Two (Oracle SE2).
Oracle SE and Oracle SE1 were licensed per socket, regardless of the number of cores (physical threads) or hyperthreads (logical threads) in the socket. This meant it was in the customer’s best interest to buy processors (sockets) with the most physical cores and with hyperthreading to get the best performance for the Oracle licensing cost.