METVs aren't that difficult to obtain if you're in your home country, and aren't at all restrictive - you can come and go as much as you please by land or air up to the 'enter before' date and you can get almost 9 months use out of a 6 month visa.
I don't know the rules of the consulates in the US (they're online though), but meet 'em and get the METV and you're good to go!
I'm pretty sure, despite the comment, that you will not be fined at the airport. It'll just be kept on record and you'll be fined the next time you need to go to immigration for any reason
At Nong Khai it closes at 10pm. However, I would advise you to get there a bit earlier as sometimes they close the Laos visa window early and then you're stuck!
You're pushing it a bit there man. You can get an extension, but after that you're going to struggle without getting a proper visa for whatever you're doing in Thailand.
Also, just to clarify, you will not be deported, either when applying for an extension in Thailand, or if you attempt to return in the future without a proper visa. If you try to return again you would be denied entry, which in most cases would result in you having to return to wherever you boarded the plane (contrary to what IOs sometimes tell people, you DO NOT have to return to your home country - though most people don't want to hang around in the IDC to argue that). Denied entry and deported are not at all the same thing. You can only be deported if you're already in the country, commit some sort of offense, go to court and get deported.
AFAIK, you don't need it for an extension of stay in Bangkok. You would only need it when switching from say, visa-exempt to Non-O, or whatever. While it can't hurt to have it in hand, it's probably fair to say that far more people don't do it in Bangkok than do (for how long remains to be seen)
If you're back before Monday then yes, for 1,000b at DMK and 1,200b at Suvarna. Note that at DMK, the re-entry permit is after immigration, before security, and at BKK it's after security, before immigration.