You can certainly file both forms. The filing of both at the same time will not adversely affect either. If the I-131 is approved and you decide not to leave there is no problem. You cannot do biometrics the same day you file. After USICS gets your application they will schedule the biometrics. It may be better to naturalize first then join your husband.
The answer provided here is general in nature and does not take into account other factors that may need to be reviewed for a more precise answer. You should consult with an immigration attorney before taking any action. The answer here is not intended to create an attorney-client relationship.
You can apply for both. I recommend that you become a US citizen because an I131 will not last you three years. The citizenship process is lasting 5 to 8 months as per the USCIS processing times. As a USC you won't have to worry about the length of your travel.
Yes, you can.
You should retain an experienced immigration lawyer to review all the facts, advise you, and handle the case. You can find one through http://www.ailalawyer.com.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.