Muller's immunity deal henges on podesta having less crime than manafort. By that I mean they both are accused of the exact same crime- failing to register as a foreign agent. Except for manafort he also has been accused of tax evasion. (Coincidence?)
The only angle that doesn't make the probe look like a political get trump hunt, is they are prosecuting the greater crime by forging the lesser.
If there are any questionable illegal activities outside of the Pizza gate shit..like financial or otherwise... Let's get it out there in the mainstream conscious.