#LightningStikes When planning a migration from Classic to Lightning don't just try and lift and shift those clumsy JS buttons and URL hacks but think about what the business purpose is behind them. Invariably you'll find publisher actions are more seamless and improve user experience for frequent actions, leveraging the differences in mandatory fields for a given action (e.g. Request Special Pricing, Escalate Case etc) and  default field values.

Also take the time to rationalise those page layouts and remove any fields which only need interaction via your new publisher actions plus you may well be able to disable validation rules and workflows that are no longer required.