that'll be biochemically complex

[EngLearner]

The following is from a YouTube video called: "The mind-bending probability of our existence | Sean B. Carroll: Full Interview."

Only in the last half billion years, has life gotten big and, you know, macroscopic. So, if we were to be able to go around the universe and sample life from various places, probably the odds are that most of the time it's going to be microbial -- that'll be biochemically complex, but not necessarily anatomically or behaviorally complex.

Can "that'll be" be replaced by "that is" or "i.e. (id est)" or "in other words"? Do I understand the meaning of what he says in the video correctly?

 

[jutfrank]

Yes, I think so.

 

[EngLearner]

In the video, he started expressing his thoughts using the second conditional, but then he switched to the first conditional. I want to continue his thoughts using the second conditional where he switched to the first conditional:

Only in the last half billion years, has life gotten big and, you know, macroscopic. So, if we were to be able to go around the universe and sample life from various places, probably the odds are that most of the time it would be microbial -- that would be biochemically complex, but not necessarily anatomically or behaviorally complex.

Does it work like that?