One thing I would say is that my Havanese turned out to be more active than I figured (or that I had read). Your apartment shouldn't be a limitation, but realize that you will have to go on pretty regular walks. At 6 months, Gracie can go a couple days without a walk, but after that she gets cabin fever.
As far as being gone all day - I wouldn't worry much about it. I'm the same as you - gone to work all day, but live close to home. At about 4 months Gracie was pretty much fine with it. Now she's 6 months, and it's just a routine - get ready in the morning with her following around... then into her crate/pen with a treat and water and she goes to sleep. I come home at or around lunch time, let her out, go straight outside so she can pee, and then I spend a little time with her (doesn't have to be much, some days I'm busy and she pretty much goes straight back into the pen). Then I come home at the end of the day, take her out really quick, and that's it.
The only thing that takes a little adjustment is that sometimes I'm ready to relax after work, and she's always ready to tear it up (having slept most of the day). But that just requires a little adjustment on my part.
So basically... I have a very similar setup, and it's easily doable. I don't think she's deprived at all, she seems very happy (sleeps when I'm gone, so it's not a big deal). You just need to commit to taking him/her out at least once during the day (even when they're older, their bladders are still small), and taking fairly regular walks. And playing