You're asking for a $500-$700 cutting edge chassis for $300.
Do you understand just how expensive KeyCult is? While you can get really close for a whole lot less you're drooling over a Bugatti when you a have a BMW 3 series budget. There's nothing wrong with a 3 series budget, it's just a long, long way from Bugatti.
There's a very limited number of aluminum boards between $200 and $300, all are Chinese, not that it's a bad thing but they're rarely as cutting edge, feature loaded or as good on fit and finish, especially compared to KeyCult. There's almost nothing with gasket mount, brass weight or a brass plate, that's an option and options add cost, and in your price range there's just not a lot of room for optional parts. In stock, good luck. Then you want to dictate all these other features, hot swap, stab mount, weight, quality, looks. I'm not saying there's nothing that matches up close to what you want, but getting even 3/4ths of these or even in stock makes it really difficult.
As for your choices
I'm curious how tall the front row on the Salvation 60 is, that has to be a really tall keyboard. Phantom 65, is done, unless you can get a used one, you won't be getting one, group buys are almost always one run only, if you miss it, you miss it. BTW, recent group buys that sell second hand fetch huge prices. As for Tofu, it could take months to reach you because shipping is horrible.
Some actual in stock, actually available options are GMMK Pro, Novelkeys NK65 Aluminum Edition, both often run out of stock though. Idobao is another brand you may want to check out, they have a GMMK Pro style (might be the same board) as well as a common TKL layout. If you're willing to wait a bit, check out KBDfans.