Its always the same. Straighten what you want straight, locally relax the rest to follow that straight edge. You could pin it, or like i do, just exlcude it from your selection
Rightclick, break is the option you are looking for. Select the edges and break em, then move the islands apart And you shouldnt need to move points closer, just raise the weld treshold. If yiu set it to 1 you should be able to weld everything in the 0-1 range into one clump :)
Ahh very ineresting, I think this gives me an idea now of how to do it! So if I understand correctly, I am to weld the fingers together first, then relax them and then straighten out the edges, then unweld the fingers? I hate to be a bother but could you maybe post individual pictures as steps or even a video? The gif is…