联合申报变RA，需要补FICA吗

如题，现f1 （第四年）opt（第二年），去年是按照NRA身份报税的，今年初结婚，目前公司不扣FICA，withholding是single or married filing separately。请问如果年底打算married filing jointly，现在要让公司开始报fica吗？今年已经过去的五个月，需要让我和公司都补交FICA吗？

情况复杂，IRS给到的文字似乎也不是特别明确，目前可以搜到的一些reference：

1. NRA可以选择被认作Resident报税：
“Generally, you cannot file as married filing jointly if either spouse was a nonresident alien at any time during the tax year. However, nonresident aliens married to U.S. citizens or residents can choose to be treated as U.S. residents and file joint returns. ” link1

2. 做了这个选择之后，全年都当作US resident。关于FICA，nonresident一方仍“有可能”可以被当作nonresident，我理解为有可能不交FICA
“ You and your spouse are treated, for federal income tax purposes, as U.S residents for all tax years that the choice is in effect. However, for Social Security and Medicare tax withholding purposes, the nonresident spouse may still be treated as a nonresident.Refer to Individuals Employed in the U.S. – Social Security Taxes .” link 2

3. 关于这个“有可能”，有哪些条件呢？IRS又给了另一个链接，里面讲了F1持有者可以exempt FICA，但是在limitation下面写到：
“The exemption does not apply to nonimmigrants in F-1, J-1, M-1, or Q-1 status who become resident aliens for tax purposes”
link 3

所以...如果是F1 NRA年底申请联合申报，就需要全年被当作resident，全年需要自己和公司交FICA？
如果确定要交的话，怎么交呢？今年已经过去一半儿了...我可以现在调整下半年的withholding情况，但是之前的是怎样补最方便呢？

还有一些延伸的问题，比如HSA，如果交了FICA应该是不可以交HSA的（因为medicare冲突）。。。我应该立刻停止HSA吗，今年已经交了的HSA该怎么办呢？

^HSA问题已解决，是可以交HSA的，medicare在65岁开始enroll

请问楼主研究的结果是需不需要叫fica呢