I'm impressed with what you've done so far. The head looks fantastic.
As for the poor ventilation, that's the downside to fursuiting *giggles*.
The lens fogging, couple of ways you can get around it I can think of, although not all are guaranteed to work. First is use a fine mesh for the eyes. Usually that's done on the toony-style heads, but I'm sure with enough time and effort you could get a good representation of a realistic tigers eye done, especially looking at what you've done so far.
I'd say the small hole by the eye is an idea. it won't give a massive amount of ventilation though, so you may still end up with fogging.
Finally, a fan in the head to keep the air flowing could work, although you'd need to be bringing fresh air in from somewhere, otherwise you'd just be moving the hot air around inside and not solving the fogging problem.
Unfortunately, my knowledge on fursuit construction doesn't amount to much, and I couldn't say who'd be able to do a suit before ConFuzzled either, let alone cheaply. My advice: keep working on that tiger, it's looking real good