Congratulations indeed! Wise move.
Mason jars are not required if you have good tins. I consider "good tins" to be the food-grade models used by McClelland or GLP. Less good are the older, more rust-prone cylindrical C&D/GLP tins. Also less good -- for loss of seal risk -- are the squat rounds as used by Dunhill and others, or the square tins as used by Esoterica, F&T, or Solani.
I still prefer to keep tobacco tinned wherever possible, to keep the aging process going uninterrupted. I would just override that concern when there is risk of tin attrition.
I would advise keeping the tobacco indoors (which is likely to see a 20F temperature swing during the year, or during any given day, compared to the garage which is likely to see MUCH more than that), if you have an extra closet (or two!). Tobacco is much more forgiving than fine wine, but you probably want to keep the temperature swings to a minimum -- particularly with tobacco containers which rely on vacuum sealing, e.g. some mason jars, or those EU tins mentioned above.