Williams can't defend small forwards anymore, Kidd-Gilchrist's 3 is virtually non existent and Johnson isn't Spurs material and his 3 is too shaky to play alongside the starters. The same goes for Crowder.
If they don't swing a trade (and we know how adverse they are to doing so unless forced), Deng, Stanley Johnson and Lance Thomas, are bargain bin options I could see them looking into.
Whether Milutinov or otherwise, once accounting for a third center, if they don't swing a trade involving the players you mentioned and/or Forbes, they could eat Metu's contract to bring in said bargain basket big wing.