Ba(acac)2, Ba(tmhd)2 and Ba(methd)2 will be soluble in tetraglyme, which is a good solvent because of vapor pressure and stabilization of electrostatic forces. Ba(acac)2 is soluble in methanol according to literature, but maybe not at room temp (did you check this?). Any solvent like tetraglyme should work; bipyridine is another.
Ba(acac)2 costs ~$1000/mol, but it can easily be made from BaCl2*2water (~$27/mol) and acetylacetone (~$12/mol). Cheaper to make. Ba(tmhd)2 can be made cheaply in two steps.
Ba(methd)2 can be made in 5 steps; attached jpg is my opinion of the best path to the ligand. If you have questions or someone wants to correct me, please post a comment.