Chelsea would be fine, considering they are not happy with Lukaku, they could replace him with Ronaldo and they would be doing fine with him at striker position instead. In fact, Bayern would work out well too if they are planning on selling Lewandowski, in that case they could sell Lewandowski for like 50 million, which they have been trying to do for a while now, and get Ronaldo for 20-30 million, hell if I know Bayern and how cheap they are, they would get him for 15 million 
All in all, Ronaldo is a great striker, even at his age he would bring a lot of talent to a lot of teams and would make them a much better team for sure.
All in all, Ronaldo is a great striker, even at his age he would bring a lot of talent to a lot of teams and would make them a much better team for sure.I think it is a pretty safe thing to say that there it is completely unrealistic that Bayern Munich will try to sign Cristiano Ronaldo, even if Lewandowski will leave the club and goes to Barcelona. There are several reasons for that. It would make absolutley no sense for Bayern to invest a lot of money into a player that is already 37 years old, even if we are talking about Cristiano Ronaldo here, he is still way past his prime in my opinion. Even if he would cost only around 20 Million € of transfer fee then he will demand a salary of at least 25 Million € per season i would guess because at the moment he gets around 30 Million per season at ManU AFTER taxes.
This is honestly the first time I have heard of such a transfer, there have not even been any rumours, I take it this is a fantasy? Why would he move to Bayern, in the German league? I think he would be bored there, even if he is in a strong team. And besides, the age, as you said, they will sell a younger player and take another one, who has a few more seasons to play?