I guess a lot of this hinges on what your common interests are.
Believe me, you're not alone in this category as one of the biggest complaints I hear from some (not all) expats is that they're bored-to-death in the daytime. And most of the expats I know don't have a large cadre of expats friends either. Most of their social interactions with other expats either happen around the bars at night - or sometimes early morning breakfast chats with a few other expats they know. That's about it.
That said, visiting the gay scene at night seems like a great way to start some new friendships regardless if you drink or not - seeing as the majority of expats you see on the scene are there for the very same reason, i.e. social interactions and building new friendships.
Also, using this forum as a way to generate some common interests among other members isn't a bad idea either. Just because the last "Meet & Greet" didn't work out doesn't mean it won't work in the future. We had a Sawatdee Meet & Greet arranged years ago at the original Memories Cafe/Sunee and a handful of members showed up, but not until after we moved the meeting date around a dozen times. The owners of Memories (Jack, Ralph & Oud) told me later that night that if they would have laid out free food and hung up balloons the place would have been packed...555.
On a personal note, for me, having a partner certainly takes the edge off the need for having social interactions with others. I still enjoy (and need) those interactions so don't get me wrong, but we do everything together...enjoy our own individual hobbies which fills most hours in the day... have each other to share with...reflect with...joke with...share meals with...debate with...laugh with...enjoy sex with...and love with. Ironically, we first met on GayRomeo and in both of our profiles we had posted "Looking for Friends" as our interest. Funny with how that fits with the conversation we're having now.
Your suggestion about there being some sort of "Welcoming" process for new gay expats is an excellent one.
My wheels are turning.