The addons Wholly and Grail work in both live and beta clients without alteration. They are smart enough to detect which client is being used and make adjustments as needed. Grail is a quest database, and there is great need to update its information for MoP beta so it can be as complete as possible when we all move to MoP in the future.
If you would like to help out, there are two major categories of help:
(1) Quest/NPC information gathering. You can do this simply by wandering around accepting and completing quests, and then submit your Grail.lua saved variables file to have any new information integrated into the database. You can augment the information gathered by turning on tracking with the slash command "/grail tracking" and then you can make comments that go into the tracking information with the slash command "/grail c This is my comment"
(2) Localization for non-English. Wholly needs UI localization, and most of the European languages are almost complete. There is great need for Korean, and both Traditional and Simplified Chinese. To help with UI localization you can input data on the curseforge.com website for Wholly.
Also, NPC names need to be localized. Basically Grail can get a list of the NPCs you have encountered and compare them to what it has in the database. If there are differences (new ones Grail does not know about) it will record that information in its saved variables file. You can ask Grail to examine the NPCs by issuing the slash command "/grail verifynpcs" and wait a little bit while it does its work (you can still play while it is examining them).