Today on MSNBC, they were discussing the issue of pardoning, and how it could be used by Trump as a pre-emptive strike to clear individuals who might otherwise take immunity deal. They were saying it would be unethical for a President to use the pardoning powers to protect himself and\or others, but they all agreed Trump likes to breaking rules if all they are "rules", and not laws, and they said there are no laws preventing a president from using his powers clear individuals so they can't be investigated.
The Bottomline to the discussion was, Trump is likely to use his pardoning power in unethical ways if it gets him what he wants, and he is willing to gamble all his political power (and Republican political power), that if he pardons all the key players, there will be no real political backlash beyond a bunch of politicians saying "oh, you are a bad boy, go sit in the corner for 3 minutes". Trump gets off the hook because there is nobody to be held accountable.
It is an interesting proposition to issue a blanket pardon to everyone in his administration past and present including Pence. As stated by the person on MSNBC, accepting a pardon would be construed as an admission of guilt. However, Trump would spin this as a way to stop the "witch hunt" so he can get on with what he promised his supporters when he was elected. He could even fire Mueller to ensure that the investigation was completely shut down.
And if the heat got too much for Trump, he could resign and then Pence would pardon him. This would all be done in the name of getting back to the job of governing.
The alternative would be to let all the investigations run their course which could be even more damning to Trump...impeachment, removal from office, but also jail time. With Trump, anything is possible. And if he went that course, his faithful base of supporters would cheer him.
History would be written with alternative facts to cast him in a positive light...
Unlikely he would pardon them all at once, but Trump is so unpredictable he could pardon several at once if his legal team says he has the presidential authority to do it. I believe he does have the authority because presidents tend to pardon countless individuals as they leave office. It is easy to see Trump pardoning several key figures currently under investigation knowing it will put an end to the entire Russian connection. He doesn't have to say anything more than "These great men did nothing wrong, and put an end to it. Next question". It might cost him a lot in terms of political backlash, but his base would accept it.