SimplyHike is made for mapsforge 0.3 which is compatible to Locus as it's the same basis. So converting it is easy - just delete all but one xml-file (the one you want to use) from the theme folder, as Locus only allows one xml per folder. If you want to use several xml files, copy the whole theme folder and rename it, and delete again all but one xml file.
Tiramisu 2.0 Beta is made for Oruxmaps Beta which uses mapsforge 0.4, and maybe Maki has used some stuff which Locus doesn't support. At least the tile resolution is 4 times as much, so it would look different. So you can try the same as for SimplyHike written above, and see how it works.