Marco should be a lot stronger then we have seen the guy is a white beards 2nd and having Phoenix ability should be op . He should be able to put up a pretty good fight against linlin
My big question is why was he worried about Perospero when BM was holding him?
Assuming he couldn't transform his neck where she was holding because she was using haki so it was like she was holding his actual neck; shouldn't he still have been able to transform whatever part of his body Pero shot at? And even if he couldn't shift that part as long as he's not in contact with seastone wouldn't he still heal and revive due to the nature of his fruit?
If Marco is hit by a fatal blow using Haki, say someone used haki and stabbed his heart or cut his throat/head off, would he die or would his fruit kick in after death the way Brooks did and revive him?