If you have dual citizenships, mention both on the form.

When I re-enter USA after being in Canada will I be able to get another six months stay stamped on my I-194 (tourist visa)?

The length of your stay in Canada does not make any difference. Your I-94 may not be stamped for another 6 months.

When is safe to change employer when GC is approved?

Having good faith is the key. You may be able to change your employer soon if there is a legitimate reason. Otherwise, a reasonable period of time...

Can I apply for college with this papers or I have to wait for a green card?

Applying for college is seperate from your green card application. You should be able to find more information from school(s) you are applying to.

Do i get learners permit when my h4 visa is in extension process

Your question is state specific. You should search the DMV website of your state.

E2 single entry visa

If your visa is a single entry, you need to apply for a new one once you leave US. The country of destination does not make any difference (i.e....

Does my husband still need to disclose arrests on a Citizenship application when the dispositions do not exist?

If you do not want this matter to be an issue on the N-400 application, you MUST disclose it, or your application can be denied.

Short answer is yes. You must show that you intend to work in the field you indicated in your NIW application.

Does that mean that 2 year rule does not apply?

You could ask for advisory opinion since there was a discrepancy in the visa and your DS.

How I can get a job offer allows me to apply for an H1B visa to live and work legally?

This is not something that an attorney can help you with. You should apply to multiple companies. Keep senging resumes.