I’m wanting to get a short and lightweight hunting rifle in 6.5 Creedmoor for next deer season. I’m also wanting it to be stainless so I don’t have to worry about it getting rained on. So this brings me to my real question, I’m looking at ordering a Tikka T3 Lite in 6.5 then having it cut down to 16.5 inches and threaded. From everything I’ve read, I would most likely have to go with 1/2x28 threads still. I have a Griffin Recce 7 to use on it, so would I be safe to thread it 1/2x28 and run it with a minimalist taper mount that has been opened up to the proper size?

I'm going to be using 1/2x28 for .30-06 so...

Even though it can be done, 1/2-28 is not the desirable choice for .30 caliber.  See the posted information from Ray at Thunderbeast Arms.
But, there might be some other options; no way to tell without knowing the barrel diameter at 16".

If you have enough room for a 1/2" thread and shoulder (about .600" diameter), there would be enough for a 9/16-24 thread and muzzle face mount, or an added collar to make the shoulder.
Many companies make their suppressor mounts in 9/16-24, but not all do.  Or, you also might have a direct thread can that is only 5/8-24.
In that case, you could use (in place of a collar) an excellent 9/16-24 to 5/8-24 step up adapter that is designed to seat on the muzzle face, from:
hughesprecision.com
They make some of the best adapters I've seen, with full length .600" threads instead of the too-short threads of some others, and their prices are lower than most.  Beautiful quality.
I recently set up a barrel in exactly that way: 9/16 threads (on a .565" diameter barrel), cut the muzzle face square with a recessed crown, and that adapter, seated against the muzzle face.
Alignment with a 9" suppressor and range rod was as perfect as it gets.

You’ll be fine with 1/2x28 on a 6.5, I’m running 1/2 on a .270 with no ill effects but that is my personal max bore for that thread. Many run up to .30 bore with 1/2, as stated earlier. Your plan to use stainless and shorten the barrel is solid.

Is there a lot of options in that thread for devices in 6.5?

Millions of FALs in .30 are threaded 9/16-24LH so I'd have no concerns about 1/2-28 on a 6.5.  Having a nice thick square shoulder to torque the mount against is also important unless your mount indexes on the muzzle face.

No, you'd have to have a 5.56 device bored out.

There should be plenty of barrel diameter to accommodate 9/16 threads if you cut the barrel to 16.5" (I'd guess you wouldn't even have to go that short to do it).  I would feel more confident with 9/16" as opposed to 1/2" on anything bigger than .224 caliber.

Of course Griffin doesn't offer their taper mount in a 9/16 thread, though I wouldn't use that reason to go to a smaller thread.  Perhaps one of their 1/2x28 mounta could be retapped to 9/16x24.

All that being said there are plenty of 308, 30-06 and 300 mag rifles with barrels threaded 1/2x28 for the addition of a muzzle brake.

Even if it will keep the suppressor attached, one concern with using minimal thread diameters is the lack of strength when ( probably not -"if") the suppressor is bumped hard, from a fall, or any other cause.
No getting away from the fact that it will take less impact to bend a 1/2" thread on a .30 caliber barrel; .264 should be a little stronger, but not enough for me.
One time I experimented with a mock up in this configuration; a surprisingly small smack was enough bend for baffle strike.  Enough to cancel my plans for such an application.
9/16" is the minimum for .30 that I have found approved by any manufacturer, except Kimber, who uses a 7/16" (Yes, Seven) thread on some of their .300 Win Magnum rifles.  
The FAL, with 9/16" muzzle threads, has those threads far up into the inside of the FH, with much of the body extending back over the larger barrel diameter for support
As long as this is a thread Thread, there is really no reason for a 1/2" thread on most .223, even ARs, except for the fact that it started out that way, and was never changed when the Military dropped the pencil barrels.  The standard .750 gas block AR barrels usually have enough muzzle diameter for 5/8" threads.  I use 5/8" on all my .223 applications, when possible.
That also makes it easy to use the 5/8" thread direct thread cans on all barrels.

But, a half inch thread can be, and sometimes is, used on the larger calibers.  Your call, and I wish you well with it.

Ive already decided to go with a Barret field craft in 6.5 and not even mess with the 1/2x28 threads.

Just be careful of the mounts and how it indexes, if off the muzzle or shoulder.  I had a QD mount on a barrel that was .720 " a BCA 6.5 Grendel.  The minimum shoulder for indexing on some of the QD mounts is ,740".  My rifle patterned all over the place.  You need to make sure there is enough meat on the barrel for it.