Certain example embodiments relate to vacuum insulating glass units having pump-out hole seals formed in connection with solder alloys that, when reactively reflowed, wet pre-coated metallic coatings, 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. SAC, InAg, and/or other preform materials may be used in different example embodiments.