wondering about greek life

It really depends on the house and generally you can answer most of these questions based on tiers. Generally, higher tiered houses have larger pledge classes, generally they haze more, they almost always have better girl to guy ratios.

A few exceptions to this are Phi Delt and Fiji usually have large PCs though they are middle to lower tier houses. SAE and phi sig, apparently have lots of hazing, not sure how true this is though.

The general vibe has changed as of late. When I showed up to campus it was a lot of unregistered events and houses kind of did their own thing. Lately, most parties have been registered more frequently and pairing with other frats has been happening more often.

Pledge classes always vary, especially in the spring. In the fall you can typically expect anywhere from 25-35 person pledge classes for most of the fraternities. Spring can be 5-15. You can get an idea of which fraternities pull in the most guys just based off their roster number already. For example, Sigma Chi has around 100 members while Lambda Chi has like 40.
Hazing is only as bad as you make it. If you're a baby and complain, it's only worse.