You would have to come to the practice at 8 o'clock now that you have made it to the team.
Do you think she's coming? I'm sure she would.
I find it very difficult to imagine anyone actually saying or writing these sentences.
The first states a definite situation, that you have made the team, and the consequence which now that calls for should be definite, too: you will have to come to practice.
The second is perplexing: the question "Do you think she's coming?" in effect contradicts your certainty. If you're sure, why do you ask?
Would is not justified in either of these; it is not used for "politeness" in this sort of context.
But the two versions you supply in the comments are entirely different.
You would have to be here for the games and any practices that you schedule, they both take place on Tuesday and Thursday.
In this one the definite situation, "now you have made the team", is gone, so we are free to suppose that it appeared in a context which expressed a contingency, a condition which might or might not be true:
Congratulations! You have made the team! We hope you will have time to participate: you would have to &c...
You may or may not have the time, so the coach sets forth the requirements; if you were able to meet this schedule you would be able to accept the invitation to join the team.
Why don't you invite Mary? I'm sure she'd come.
The question makes it clear that you don't know whether Mary has been invited, so it is quite easy to infer that her coming is contingent on her being invited:
I'm sure she would come if you invited her.