I would gut it out inside. Then remove only enough siding to replace each window, framing for new sizes as you go. Remaining siding stays to protect the house. Install new construction windows with flanges and tape/caulk them to be weather tight until siding is done. Siding would be good at that point but can wait if weatherproof. Then wire, plumb, insulate, etc. Then do walls and trim. Side it before it leaks.
The trim on that window is part of the siding system.
Trim the outside of the windows to your taste and budget with the siding job.
The trim on that window is part of the siding system.
Trim the outside of the windows to your taste and budget with the siding job.
