My question on kaddish was well answered.
The answer said that the Vilna Gaon preferred the word כּרְעוּתֵהּ with the dagesh in the chaf, because that word is not connected to "ברא", but to the beginning of the kadish ("יתגדל ויתקדש... כרעותיה") - i.e. that He will be praised according to His will.
Now the Mishna Berura 56 (1)  says
אחר תיבות כרעותיה יפסיק קצת דתיבות אלו קאי אלמעלה על יתגדל
After the words כּרְעוּתֵהּ one should pause because those words refer to the יתגדל above.
The words in bold sound very much like the answer to my previous question.
Q1] Does the Mishna Berura pasken that we should pronounce the word כּרְעוּתֵהּ?
Q2] Most of the siddurim I have seen have כרעותיה without the dagesh. If the answer to Q1 is yes, whose opinion do these siddurim follow?