The news has been awfully quiet with respect to Paul Manafort and Michael Cohen
Once the federal government get it's talons in you, you are in deep trouble. The sentencing structure of the federal court is far more severe than individual state charges. A crime under a state statute that might get you 2 years in prison would potentially get you 10 - 15 years of federal time. The federal courts use what are known as the "sentencing guidelines". Those guidelines are very strict and complicated. Almost every federal defendant cringes when they see the possible sentences as calculated by those guidelines. I am sure Manafort and Cohen have had the same reaction.
Once the severe sentence is known, most defendants want to know if there is a way out. The most common vehicle is called a Rule 11 "proffer". This is essentially cooperating with the Feds. It is a conference set up with the US Attorney, the Defendant, defense counsel, and the agents investigating the case. The agents are always looking to work their case "up the ladder" to obtain information on larger scale offenders. This conference is in private and is not recorded. Even the Federal Judge assigned to the case is not aware this is happening. Any statements made by a defendant in that proffer cannot be used against them with very few exceptions. If the defendant provides useful information the government can then file a Motion for Substantial Assistance with the sentencing judge. It essentially says the information provided by the defendant "substantially assisted" the government investigation and requests the court to reduce the penalties. Although the Federal Judge is not required to abide by this motion, most judges do so. This tactic can even be employed where a defendant is facing a "mandatory" sentence which means, by law, the judge cannot sentence the defendant to anything except prison. Once the judge accepts the substantial assistance motion, the judge can reduce the penalty to virtually anything.
Manafort and Cohen were each facing substantial prison time. I am sure at some point the Feds came forward and made them an "offer you can't refuse". In these circumstances the self-preservation instinct is very strong and former allegiances fall by the wayside. I suspect this is what may be happening and why there is no current news regarding these cases.