Just tested it at Goldenrot City at the Pension for Breeding.
Although you gotta be quick and press as soon as you enter the game x (as the RNG is not calm there) you still can verify your seed fine with the Elm Method and also advance your RNG with it, you gotta be quick then and press as fast as possible A so just like in DPPt but the Seed Verifier works there also just fine.
Tested with 3 Roamers out, I guess it should also work with 2 Roamers out.
Although you gotta be quick and press as soon as you enter the game x (as the RNG is not calm there) you still can verify your seed fine with the Elm Method and also advance your RNG with it, you gotta be quick then and press as fast as possible A so just like in DPPt but the Seed Verifier works there also just fine.
Tested with 3 Roamers out, I guess it should also work with 2 Roamers out.