The commital proceeding is a formality nowadays. Your case will go straight to Crown Court. In the old days, and theoretically now, the defence could make a submission that there was no sufficient evidence to send the case to trial. This was only very rarely done because a) the magistrate(s) would commit on the barest evidence b) the defence, by their submission, often alerted the prosecution to gaps and deficiencies in the evidence, which the prosecution would put right before trial, making things worse for the defence and c) if the submission succeeded, the defendant was discharged but that discharge was NOT an acquittal. The prosecution were at perfect liberty to try again if they found further or better evidence or (in theory) even if they didn't.
Therefore your solicitor is telling you to wait to the trial.
What your co-defendant does is a matter for him but you shouldn't be speaking to him to influence him one way or the other, if you are so tempted.