Could I be facing a lawsuit in the future if my business becomes successful and its name has a 2 letter spelling difference from another business?

It's possible. Infringement is based on whether there is a likelihood of confusion. One factor to be considered is whether the names sound alike.

Only if there is a likelihood of confusions between the two businesses.

The LLC is not a trademark, it is a form of business organization. If you are using a name and/or mark to identify services and that name is confusingly similar to a (preexisting) trademark, the preexisting trademark owner may require that you cease using the confusingly similar mark. Deciding whether there is requisite confusion depends on the nature of your product(s)/services, the region of extant use, the (previously) trademarked product(s)/services, and the prominence of the trademark in the region(s) of use. Infringement may also depend on whether your and/or the other trademark(s) are registered (which gives a trademark national scope). You probably need an attorney to help sort these things out for you.