Some people really want/need an en-suite bathroom. Some people would like one, but can live without it if everything else--location, price, other amenities--fits their needs. Some people really don't care either way. And some people really don't want one. So if you buy this condo, you have eliminated the "really want/need" folks from your potential buyers and renters. But you still have a fairly large pool of potential renters and buyers to draw from. If you add the shower to the downstairs bathroom, I think you will make the condo attractive to non-related renters--three grad students, say. Do other units in the building have en-suite bathrooms? If so, then not having one could be a liability. But if there are other units without one, and the building itself is a desirable place to live, then you should be fine. You might have to lower your asking price to draw people in, but that would be the main drawback that I can see.

Thank you to everyone for their ideas and comments. We are currently working with a designer with engineering experience. There will be another ensuite room downstairs which could function as a 2nd master for resale concerns. @new-beginning - You got the idea for why I don't want all three kids upstairs - thank you! When my sons are in HS, my daughter (and her friends) will be 4-11. My boys are VERY respectful, but I think we all know how *some* boys talk and what they talk about in HS. My boys WILL have friends over and if they're all upstairs having a sleepover or just hanging out, watching a movie or whatever, I really don't want my daughter (and her friends) hearing conversations, etc. that are not age-appropriate for her/them. @Beth H and bossyvossy - I am most definitely NOT letting my kids decide anything about this house! They actually don't want to leave our current house at all :) They won't have any say on anything in their room or the house set up or anything! This is all for how we believe the flow will work best for our family. @chocolatesnap - You may be right, but right now, we cherish our time after the kids go to sleep. That's the only time we have to watch a movie together or enjoy a glass of wine or whatever. I am sure that we would still be able to isolate ourselves on the same floor with the kids though. Thanks again, everyone. I think while the upstairs retreat still sounds amazing to me...the costs involved with adding a second floor probably outweigh the benefits.

I haven't yet installed a solatube - but if any small area has no floor above it, bring in any light ya can !? If this helps: consider what activities would be best with/ without sun and glare [tv maybe without]... and best with open windows....

Sounds very reasonable to me, but I guess it depends on where you live! We just combined two bathrooms into one, larger one, converted a small bedroom to a bathroom and separated a large bedroom into two and it was about 90k.