I'd go for a PF as first priority, then a cheap veteran PG second. I don't buy this Porzingis at PF next to Al or Rob talk. I think Porzingis is the unquestioned starter at C and they find a tougher, dirty work, rebounding/defensive PF with more mobility to play alongside him. White, Brown, Tatum, power forward X, and Porzingis should be the closing lineup most nights. Who's going to be taking all the pounding inside for most of the year? Grant might be gone and Porzingis isn't going to want to do that.
If Brogdon moves to the starting lineup, all of a sudden Pritchard and Davison are the only backups. I would feel better if you had another option there.