第一计划也叫403B?我记得我们这里的新雇员可以选择Retirement Savings Plan：

You contribute 8.0% of your eligible earnings. Employer matching
contributions begin with the first full payroll after your plan election
is received. Your contributions and the employer contributions
will be made based on your full salary, up to the IRS 401(a)-17
annual earnings limit. 

你的第一项是必需的，主要是拿到match。自己投资，走index，自然也是定投。。。2和3，4和5当然是有多余的钱才会考虑。你应该没有Social Security tax。看年龄和家里另一半的收入，尤其是退休后的收入来决定投多少到Roth。我自己还会看每年的margin tax rate。我是通过401K/403Bcontribuion的多少来控制每年的margin tax rate的。