do I have a 26 fork using 27.5 wheel? I realize I've been riding for a year using this configuration, I have a suntour sf13-xcm-ds-hlo-26-100 (which I think was designed for 26). Suntour website doesn't provide full info about the Fork, will I have a problem with the wheel or the fork?
If the wheel fits..... 

If you have been using it, then no, you won't have problems. Its not that uncommon for people to shoe horn a 27.5" wheel into a 26 fork or frame. just running a front wheel will slightly change the bikes geometry, but not enough to make a big difference.

Where you can run into trouble is if clearances are not enough and you ride in muddy conditions, causing build up and blocking.  

When you replace the tire, you will need to be careful to get one that fits. Most 27.5" "upgrades" require a smallish (2.1) tire, and you will want to avoid ones with aggressive side lugs unless you can try before you buy.