I am also expecting: Smart, Brown, Tatum, Theis, Thompson
I don't share the enthusiasm over Grant Williams. I remember that Ojeleye played well in the playoffs a few years back and there was hope he would make the leap. I still like GWill, but as a versatile player off the bench (primarily as the back up to Theis), not as a starter. And I like RWill to play more regularly as a decent back up to Thompson.
For this lineup to work (at least at the level that the Celtics are aspiring to), Theis has to both adapt and improve his game over last season. He needs to improve on the 33% 3pt shooting from last season (he was 39% in 2018-19) and bring a little more hall handling and passing. I don't think this is a huge leap though. I think he can do it and be a decent PF on this team.
In the end, this line up, with Smart over a healthy Kemba Walker, may not have enough offensive punch. I don't think adding Teague in for one of the bigs would help all that much. It is what it is. I think we are solid still but we have taken out Walker (to start due to injury) and Hayward and added Teague and Thompson. It will be a lot better when we get a healthy Kemba Walker back.