Isiah is known for being harsh and a jerk to his players, plus he doesn't know the triangle offsense, Phil only hires [Swearing is not permitted at Clublakers. You must edit this post prior to submitting.] coaches who are pro's at using the offense. Tex Winter invented the triangle offsense, next year will be Tex's last year coaching, he's been coaching for the past 60 years.
Anyway, after next season they will need an assistant coach, They likely nominees like you said probably would be Brian Shaw, or Ron Harper. You remeber when Harper visited with the Lakers for a week last year? Tex was expected to retire last year so maybe he was visiting with Phil.
Byron Scott would get hired before Isiah Thomas. I think there's too much bad blood between Thomas and the Lakers. But if they were to hire another coach it would be someone with great knowledge of the offense, i.e: Harper, Shaw, H.Grant, Jordan, Pippen, Kerr.