I need a recommendation for which is the best to choose from of these three in a combat situation.

10mm SMG (Highest DPS)
Ranger Sequoia (Highest Damage, Second lowest DPS)
Thump-Thump (Aoe, but lowest DPS)
And ammo doesn't really matter, I'm not on hardcoe mode and have a great barter/repair skill.

And I would like help choosing between these for a stealth weapon:
^(Keep in mind that I will be using the Professional perk)

12.7mm Pistol (Higher Damage, However a very high spread)
10mm Pistol (Better Spread, especially with the laser mod, but I don't know if it affects stealth)

Thanks for all the help.

I'm not quite sure what exactly you're looking for because your post asks for the best SMG and Revolver, then claims the 10mm SMG has the best DPS (pretty sure it doesn't), you name two pistols and for some reason Thump-Thump, a grenade rifle, is in there too.

But uhhhh, Lucky's another really good revolver, and I'm pretty sure Vance's 9mm or the GRA 12.7mm SMG are gonna be the best. Or Sleepytyme if you're trying to sneak.

The best out what the options are, sorry...
REally didn't follow with the title either...

Tommy Gun and Ranger Sequoia/Hunting Revolver.

It depends entirely on the combat situation on which of the three you mentioned are better. For an all-rounder I would keep Thump-Thump though, I'm not a huge fan of the Ranger Sequoia and the 10mm Pistol is simply outclassed by another SMG.

Best revolver in my opinion is Lucky, I personally find it far superior to the Ranger Sequoia as a sidearm.
Best SMG I would say is the 12.7mm SMG; it can be silenced, its light and it has a very powerful punch for an automatic weapon.
Note: The .45 auto SMG may be called an SMG, but it still weighs 11 freaking pounds.

As for which of those two pistols is the best for sneak crits it, yet again, depends:
The 12.7mm Pistol has much higher damage, DPS and crit damage(nearly double on all three stats).
The 10mm Pistol is more accurate and even more so with the Laser Sight mod, but this is off-balanced by its inaccurate sight.
They have the same durability.
The 12.7mm Pistol weighs half a pound more.
The 10mm Pistol's magazine holds 5 extra rounds or 9 extra with its Extended Magazine mod.
The 10mm Pistol is an Improved Holdout Weapon.

My advice concerning these two weapons is that if you plan on using it in a casino then the 10mm Pistol will do, the 12.7mm Pistol should be used in all other circumstances.
My overall advice concerning stealth weapons is to get the Sniper Rifle.

Sorry, but I don't have any DLC (Nor will I probably ever)

Magazine isn't a problem for me, nor the sights because I prefer to play without true sights.
Would the 12.7mm be accurate enough for the average close-range shot? Getting closer isn't a problem in most occasions, but obviously some enemies would make trouble.

I assume you mean the silenced Sniper Rifle? There is the COS Silencer Rifle in Old World Blues that is unique, silenced and an all-round great death-bringer, but I was talking about the vanilla Sniper Rifle with the Silencer mod.

Note: I recommend you try them, they are definitely worth the price.
The 12.7mm Pistol is inaccurate for a pistol, but its still fairly easy to take head shots at close to mid ranges.