You can call it whatever you want. And using one term doesn't discount the other. It doesn't change what an Invasion is. But feel free to try and change commonly held word definitions like a Progressive and make language less direct and useful.
No. Just because you have a military base or leasing agreement somewhere doesn't mean you get the right to take over the local government buildings, seize border crossings and disarm the local Ukrainian forces, and import more little green men to facilitate the annexation of the region. It's still an Invasion. Unless the entirety of Crimea was their military installation, which I'm assuming was not the case and thus your counterpoint is irrelevant.