Can an arrest warrant be electronically filed apon the arrestee after he has already been arrested?

There could have been another warrant out for his arrest, for a different issue. Otherwise, it does sound fishy.

How long I looking at in prison

The above answers are correct. There's also the possibility of having consecutive sentences.

Was this a false arrest?

There's not much there given your facts.

What do you think the outcome will be for his first court hearing and what can I do in the meantime to help him get home

He will likely have a cash bond set. An attorney can help keep the bond amount as low as possible.

If I, a 15 year old were to have sex with my 18 year old boyfriend, with parental consent, could the state of Ohio press charges

There are many ways that this ends badly for your boyfriend, maybe even your parents. Few ways that this turns good. This is not a good idea.

If she consented will I get in any real trouble? Also will I get in trouble for seeing her without her parents permission?

Do you care about her enough to catch a contributing charge or a felony charge, that you may or may not beat?

I agree with the answer above. If the claims are not correct that'll be an issue for the discovery process, and or subsequent trial.

Will I be taken back in front of the judge? do I just go to jail to serve time? What are my rights in ohio.

It sounds like you'll go back in front of the judge to explain why you haven't completed your community service as a term of probation. You'll...

What you have said so far does not appear to be either perjury or falsification. If you attempt to lie on the stand you can be charged with...

Whats my chances of jail if I have my 5th driving under suspension but I got myself an attorney.?

Your chances of jail are definitely high on your 5th offense. Your attorney will be the best person to ask how high are your chances and how long a...