Luigi seems like a low or bottom tier. Too floaty and slow in the air to land well, exploitable recovery and has a surprisingly hard time finding kills despite having some good raw kill moves and f-throw as a kill throw because of his mobility and few kill confirms.
Sheik and Zelda are probably somewhere in mid tier, which Sheik being better this time around. Both were nerfed pretty hard, Zelda especially. Sheik still has really good mobility, a functional grab game and good edgeguarding. She has a decent time finding kills, but doesn't kill very early unless she gets a gimp. Zelda's neutral actually seems a bit better with her new jab and d-tilt despite lighting kicks having a bit more landing lag. She doesn't kill nearly as early as she did and before, and her grab game is much less threatening than before with b-throw not killing until like 130% now. She can't really get an early stock off of a grab anymore without getting an U-throw -> F-air DI read. It's harder to combo out of N-air too and U-smash sucks as a kill move now, making her anti-airs not too threatening (doesn't help that U-tilt no longer kills now either despite being faster). Sheilda is probably upper mid tier or high tier this time around just above standalone Sheik.
I agree with the person who said Yoshi's worse off now, I think he's low tier or bottom tier. Having a f-air with more range is good, but his grab game kinda sucks now (and he already has a super laggy grab), he can't really kill, he can't stall in the air as long and I can't find anything super good about him yet.
Bowser seems very good. Bit of trouble landing since he's big and kinda floaty, but n-air, d-air and Bowser Bomb help him out a bit. He has ridiculous amounts of power with his U-throw of course having a great combo game at low-mid percents. Floaties die at like 50% to U-throw -> U-air. His f-air is also ridiculously strong with great disjoint as well. Fire Breath allows him to pose a threat from long range and steps up his edgeguarding a lot. It's very good against spacies and Ness offstage in particular. The autospacing/backward movement in the air after using it is also pretty helpful. Bowz also lives forever and has a decent recovery. I think he'll for sure be higher despite, not having the best startup speed on his attacks and having trouble landing sometimes.