To be honest, I can't say for sure that if Andrew had been played by anyone other than Tom Lenk that he'd have developed in the way he did. It did seem at first that he was just overly needy and was the kind of person who really admires his alpha male. Look at the people he "loved": you have Warren, Spike, Xander (who, towards the end, was one of the most masculine presences in his life,) and Anya. Anyone who claims Anya was not an alpha-male can try saying it to her face. 😛 I just think Tom really enjoyed playing up the bundt-cake moments. It also makes perfect sense that Andrew would enjoy dressing up as James Bond with two beautiful women on his arms. After all, that's exactly the kind of thing that Warren wanted to be.
It's difficult to tell if Andrew was anything other than deeply obsessive. I'm sure Tom Lenk had a huge influence on the character, however, and I think that the hints were flying left, right and centre during Season 7 and into 8. So, I don't know if the writers ever decided, but I'm sure Tom was playing him as gay.