I don't think that would happen - if GBC is suicidal they will watch him very very closely. The police would want a conviction, not a dead suspect.
I am no legal eagle, but I doubt he will get bail. Firstly what has he got as surety, secondly this is such a high profile case and he is the "face" of the crime, the prosecutors wouldn't want him in the community were he could hamper the case, there seems to be little precedent with accused murderers to be released on bail and the question of the girls would come into a bail consideration. There would be a public outcry if the girls returned to their dad.
This is written purely from a personal perspective (I'm no psychologist!) - but I honestly believe that if (IF) someone is capable of harming their wife/the mother of their children, they would also be capable of harming their children, if the right circumstances arose. I cannot see why they girls would be considered safe in his care given what he has been accused of. Please someone tell me I'm wrong.