Not exactly. Only Jem'Hadar (Space and Ground) and Tholian (Ground only) are obtained at Mk XI and upgradeable to Mk XII using Lobi. All others are either obtainable through a mix of marks and dilithium (KHG, MACO, Omega, Romulan, Reman) and come as whatever mark you select, including Mk XII, or are only available as Mk XI (Aegis, Breen) and cannot be upgraded.
Also, lockboxes give a minimum of 4 crystals, and can give a lot more; I did get a 50 crystal box once, but those can't happen often. However, I do get 6-10 crystals on a fairly regular basis.