Nah, Garcia is usually correct and probably is correct here that SA left themselves the option of going over the apron. They will not do that this season, but it doesn't hurt. Though Paul may have meant non-taxpayer MLE if he was talking about the hard cap. You don't have to declare which one you use. If the contract would fit into the tax version, the NBA lets it go.
Yes, it would be hard, but not impossible. Tony, Kyle and Bertans getting big paydays combined with Leonard being traded with the team picking up salary or any other trades where SA gains against the cap would get them closer. Remember in 2015, the Spurs went from under the cap to over the tax in like one day of signings.