Does an arbitration agreement get voided after expulsion at a vocational school?

You are encouraged to demand arbitration if you can.

Can I sell the property and do i have to split the money with my siblings

Depends upon whether your mothers estate was probated or if beneficiary deeds were used. Let a local attorney review the documents before doing...

The person responding is a "program analyst," not a lawyer. Can this be interpreted as "practicing law?"

The practice of law can be broadly defined but quoting cases isn't likely to be construed as one of the acts.

What would be my tax filing status?

It appears the question has been answered sufficiently.

Will i get money from this arbition

An arbitration can award damages but who knows if that is your specific question.

I don't know what to do about non-payment of child support

An order remains in place until modified. Let him threaten all he wants but only become concerned if he files a motion.

IRS taxes

I suspect this is a good question for an immigration attorney eh or accountant will similar skills.

Can I sue or am I screwed?

Unless you have a guarantee I suspect the at will presumption "screws" you.

Read the terms of your written agreement carefully to see if you may terminate. Without reviewing it myself it's impossible to tell.

Can i file a lawsuit against them and what would i classify it as

I'm sorry but that is unlikely as your were under their care and control and unless they neglected or abused you poor decisions are not compensable.