You're through entry in less than 5 mins and through exit in less than a minute if you're from one of the countries that can go through the automatic gates (you just have to submit your MDAC before
Yes, if you leave on the 19th and return on the 19th you will be given another 90 day stamp. However, you should search the forum prior to leaving and some of the Laos borders do not allow same day return (although, this may only be enforced with visa exemption border runs, I'm not 100% sure, so better to research)
The limit has been removed, however you should note as always, it's down to the immigration officer you're facing at the time and you're not guaranteed entry
the requirements vastly differ from office to office. You would be better going to your local IO and asking for the list.
But in short you will need at least the forms, your marriage certificate (certified and stamped by your embassy if you married abroad), 400k matured for 2 full calendar months prior to applying (if applying for the visa inside Thailand you just need the 400k in the bank, doesn't need to be matured, if applying for the extension, it needs to be in the account 2 months prior to your application being submitted but it can be withdrawn once the stamp has been obtained), pictures of you both together, in your home, around your home etc and a map from your home to immigration (some want a Google printout some want it hand drawn), oh, and your wife must be with you when you're applying.
I would highly suggest just having two Thai bank accounts. And using one of them for only 800k with a couple extra 1000s to cover the yearly fee for a while.
you need a job offer and paperwork from the business for the visa and then you need to actually be in Thailand, have all the same documents + more then go to Work Permit office with your employer
depends on what you do for a living, for example, a legitimate teacher working in an international school is being paid far more than most teachers in the west and that's without considering the vast difference in the cost of living.