The photo below is my suggestion for colour of floor. Furniture should be darker - similar to below. For the rug - choose one colour from the artwork and find a similar coloured rug. Don't put a mantle over the fireplace - it could be a health hazard - bumps and bruises. Blinds - unless you want them to make a statement I think white - to match window frames would be fine.

Did you decide which timber to use. Carpet squares work well just make sure the over locked edge isn't too tight as it will cause the carpet to curl up, you can also use sisal the same way which you can take outside and hose down. With your table and chairs on timber it's all a bit timber and would be an idea to just keep the two carver chairs at the end of the table and introduce some other chairs to soften the setting, could also be better chairs for little ones to sit in.

If you were selling , are you sure you will recoup the extra $$$$ ? Get it wrong , and a potential buyer will walk and/or offer $50k less , whereas if you leave it as it is , they will know it needs replacing , offer $10k less , but you have gotten an offer ! Just me , but what I would do is rip up the fake tile lino in the foyer ( I assume it is lino -- it doesn't look to be 'proper' tiled ? ) , and do that in a darkish timber laminate -- slightly lighter than the front door , slightly darker than the stairs . Or go really dark -- almost a dark weathered grey or a similar dark brown to the drawer unit in the lounge -- the rest of the colourings will lighten it a bit , but it will all tie in . OR actually tile it , maybe a black or charcoal gloss marble or marble effect with lighter streaks through it ? The house and colourings look an older style , this continues that theme , but I feel white or beige tiles would look too bland . $2k max instead of $10k -- marble tiles may be more than $2k , but up to you .

With pine flooring a clear coat will go quite yellow over time. You can either stain to darken the timber or you can a natural raw look finish similar to a white wash that will keep it light. Problem with pine is that’s it’s quite soft it will dint and scratch more easily and a darker stain will highlight these opposed to a lighter finish.