Certain example embodiments relate to vacuum insulating glass units having edge seals formed in connection with solder alloys that, when reactively reflowed, wet metallic coatings pre-coated on the glass substrates' perimeters, and/or associated methods. The alloys may be based on materials that form seals at temperatures that will not de-temper glass and/or decompose a laminate, and/or remain hermetic and lack porous structures in their bulks. Example alloys may be based on inter-metallics of Sn and one or more materials selected from post-transition metals or metalloids; Zintl anions (e.g., In, Bi, etc.) from Group 13, 14, 15, or 16; and transition metals (e.g., Cu, Ag, Ni, etc.); and excludes Pb. Thin film coatings in certain example embodiments work with the solder material to form robust and durable hermetic interfaces. Because low temperatures are used, certain example embodiments can use compliant and visco-elastic spacer technology based on lamellar structures and/or the like.