I have a friend who did this floor in her house. I am a flooring person and had to bend down and look and touch to tell it was not real. Great stuff. I like #1 best. Contrasts the best with the cabinets and seems to blend best with the doors and trim. It might make the space seem lighter. As lots of wood can darken areas somewhat. #3 is second choice as I like it better with every thing BUT your cabinets. It's ok with cabs as it has some dark areas and is a 'louder' sample. But seems more contemporary. I actually like it the best of the samples by itself. Just not with your cabs as well. Do not like any of the others. Not enough contrast with the other woodwork especially cabinets. #5 looks the most dated and unreal. Others seem too dark. I would keep the doors wood stained as they are but paint the trim. It looks like it needs sprucing up and with all other finishes changed will look more like it needs it. I'm doing stained doors and painted trim in our new house but realize others may not care for the look. I do like the vinyl planks though.

I'm not fond of quarter round either but you might need something to cover up small gaps at the edges and between the baseboard and the subfloor. Consider buying shoemold and staining it to match your newly finished base. It's generally about the same height as quarter round but not as wide. It's a vertically oriented molding so it should match the baseboard.

I like either one. I would compliment the ceiling colour. Are you going to update the paint? The Terracotta colour on the wall could do with an update. A lighter wall would allow you to put down a wood floor without going too dark in the space. Please be aware that the wood (as light as it is) will cause the space to become 25% - 35% DARKER. Which will probably require an update in the paint (especially any walls that are like the Terracotta) and an update in the lighting scheme. The samples you have should be put up against the wood TRIM and the fireplace. And then you view the samples through all 5 lighting conditions in the home (morning, noon, afternoon, evening and nighttime). Once you have viewed the samples in all 5 (FIVE) lighting conditions, then you can pick the one that best suites your situation. Personally I like the lighter one myself....but that's just me. Please remember when installing vinyl flooring that the subfloor requires LOTS AND LOTS of attention (ahem...money/time/materials). Carpet has been used to hide HORRIBLE subfloors. Be prepared to spend $1 - $5/sf on the subfloor prep alone. Make sure you have it in the contract with the PROFESSIONAL installer (not the guy from Lowe's or Home Depot) that you want PLENTY of subfloor preparation to ensure a really nice appearance of the finished floor.

The only thing I can say is try to get as close to 3/4" thick with the thickest wear layer possible (as close to 6mm as possible...nothing less than 3mm). The narrow strip engineered will get you something....but less than $5/sf is risky business. You would do MUCH better with a HIGH END European Laminate for $5/sf than you would a bottom of the barrel engineered hardwood for the same price. And after that, you want to increase your budget. If you can't do that...then do what you think is best for your situation. I would prefer a high end laminate over a cheap-cheap engineered hardwood.