So for accounting purposes there are 66 days left in the NBA season. A rookie minimum contract for an NBA player comes out to roughly 7,315 dollars a day. If they stay under the 14-man roster limit for the full 14 days allowed that would mean they could sign Max Shulga/John Tonje for a total of 52 days at 7,315 dollars a day or 380,400 dollar each, rough 761,000 total and stay just about 80k under the tax for the year.
Basically, expect them to run with just 12 guys through to the all-star break then add Tonje/Shulga on rest of season rookie min contracts at some point before coming back from the break.
Signing Ron Harper Jr is actually much more difficult. His minimum for tax purposes is the 2-year vet minimum which comes out to 13,196 dollars per day on a pro-rated deal which very quickly eats into their 840K of room. Probably why they brought back Tonje in that trade to begin with. If they want to add Harper to the playoff roster it will have to wait until very close to the end of the regular season. Not a big deal, he still has enough regular season eligibility to play out the year on the two-way contract.
I think there are also more convoluted stuff they could do involving 10-day contracts, but the simplest path is just signing Shulga/Tonje coming out of the all star break.