Once divorced, is there a legal bond/relationship with the ex-spouse?

No, unless you create one or leave one intact that predates the dissolution.

There is no legal bond, although you may each have legal obligations that have to be carried out per the terms of the divorce judgment. You may also have a continuing relationship, for instance to co-parent children.

No, unless you continue to hold assets or debts in common, or unless there are duties or obligations established in the divorce decree.

Only if you haven't divided the community. Otherwise the only bonds are emotional.

Only that which is defined by their remaining joint contracts and the divorce judgment.

No, the whole point of the divorce is to sever and completely terminate the marital bond. Certainly, some divorced couples have to remain in contact (a relationship of sorts) if they share custody. If were asking for purposes of who might be liable for certain debts, then that is a further inquiry that would entail looking at who is actually listed on which debts, when the debts were incurred and for what purposes (marital/benefit both parties or for only one spouse's benefit/expense), who has made any payments on them during separation and post divorce, and whether either party filed for "equitable distribution" (property division) before the divorce was final