Answer to the first question: Generally if you are on a Hong Kong contract, Hong Kong law applies. Global Policies are general internal mechanisms of a company that can change at any time. Severernce pay in Hong Kong is the following:-
"Additionally, long-service payments were introduced in 1986 for workers, who have been employed under a continuous contract for more than five years, and dismissed for reasons other than redundancy, lay-off or serious misconduct justifying summary dismissal (sec. 31R, EO). The method of calculation of a long-service payment is similar to that of severance pay (sec. 31V, EO).
The amount of a severance payment to which an employee is entitled in any case is calculated as follows (sec. 31G, EO):
* For monthly rated employee, two-thirds of his/her last full month's wages, or two-thirds of $22500, whichever is less; and
* In any other case, 18 days' wages based on any 18 days chosen by the employee and occurring during his/her last 30 normal working days, or two-thirds of $22500, whichever is less,
* For every year (and pro rata as respects an incomplete year) of employment under a continuous contract by his/her employer.
An employee is not entitled to a severance payment in case of dismissal (sec. 31C, EO):
* Where his/her employer, being so entitled by reason of the employee's conduct, terminates his/her contract of employment without notice or payment in lieu;
* If, not less than 7 days before the relevant date, the employer has made to him/her an offer in writing to renew his/her contract of employment, or to re-engage him/her under a new contract, where the offer is for suitable employment, no less favourable to the employee than before, and the employee has unreasonably refused that offer; and
* Where, having been given notice of the termination of his/her contract of employment by his/her employer and where he/she leaves the service of his/her employer before the expiration of that notice."
This is the bare minimum. However banks will often want you to sign a "compromise agreement" in the agreement you are required to undertake certain provisions such as not poach customers or compete against your former employer, poach remaining employees etc. In return for signing such an agreement the bank will offer you more than statutory redundancy pay.
If the bank only offers you the minimum, I would not sign any form of compromise agreement.
Second Question: Depends on your employment contract and any compromise agreement you sign
Last Question: Bonuses are generally considered totally discresionary unless they are explicitly written out in a contract.
If you want to fight this through the courts bear in mind that although the employment tribunal system can be used they are likely to refer a complicated case like yours to the courts, and your legal fees may well eclipse the bonus and severance pay at stake.
You may want to raise an internal grievance (at bank HQ) instead with regards to your severance.