Hang shades and/or curtains at the ceiling or from the ceiling.

Or equalize all the curtains/window treatments at the same height (of highest window(s) in group).

But, I think, overall, hanging at the ceiling or from the ceiling, would be good for your space - would give the rooms more height.

It is the preferred way to hang drapes, etc. - in many design setups, and in your case it could be helpful for evening out the window discrepancies, also.

Congratulations on your first home!!!!! If your priority is privacy and insulating, I would recommend a light filtering , top/down bottom up cellular shade for all windows except the kitchen sink one. Cellular shades can come in large sizes and they have the least amount of stack when they are completely opened. For the kitchen window, I would recommend something pretty, but easy to clean since in is right above the sink( things splatter up when cleaning pots and pans). You could do a faux wood, screen shade, or a woven wood on this window.

At a later date, you could add drapes or window coverings to bring in pattern color, or simply softness. I would follow the suggestions from freedom place 1.

Good luck!

Between your corner window and kitchen window, and the fact that as you say you're dealing with so many windows of different sizes, I'd be tempted to call a professional. Have you looked at Houzz listings for Seattle area pros for this? I looked quickly and here's one with five good reviews,

https://www.houzz.com/pro/jpitzler/shades-of-elegance-kirkland-wa

Someone local would also understand better about maximizing the local light and insulating for the the climate.