O My Gay Havana, Hannah! Others have told you where the gays congregate, and yes at the Coppelia, YARA or La Rampa its a jumble of gays, gay-4-pay, curious teens, clueless coe-ed tourists and older papirikis from Yuma (mostly Italians, Canadians, Germans), along with anyone else going to Coppelia across the street. Mind the Age of Consent: its 18 years (and check carnets for DOB.)
If you know how to cruise (eyes, dearie, eyes), you will meet someone - anyone! - in a matter of moments. Be selective. The assertive ones are trade, and want $20-40. If you take the initiative, and approach the shy student/out-of-town types, you will more likely find a sweetie and friend who isnt greedy or shady. Be generous. I think the best guys are just met casually on the street, in a shop, or waiting in line somewhere : pursue the talent! Cubans male & females are all about checking each other out, so dont you worry about discretion.
The fiestas are a Don't Miss, but you should take a few of these new friends, no? They will negotiate your $10 taxi (for 2 or 5 people) to the party ($1-3 entrance, per person), an open air disco out in the boonies near the airport in most cases. You can meet guys there too - but your dates will be quietly jealous. Dear me, it can be so overwhelming, scheduling all these appointments.
Cuba may be be Communist, but cosmopolitan Havana is definitely not anti-gay. Occasionally, the authorites discourage action in the parks, or the gatherings of hundreds on the Malecon, but individuals arent bothered for their sexuality. Trannies shop and carry on in broad daylight, unlike most of the Anglo world. And its very very metrosexual, or just super "sexual," so you neednt feel afraid. Feels like I am always telling the taxi drivers that I am not interested, jejejeje. You'll love it!!!!!