1) for quick wipe just push up to the point just before it clicks up, if you know what I mean.
2) to turn it off you press it in again, the same as to get it going.
3) handbrake light is also connected to brake fluid level, either your brake fluid is very low (replace ASAP) or the handbrake switch is sticking, which means removing it and cleaning it.
4) to go as low as possible just wind the coilovers down, you could roll the arches, or get some arch extensions, or get lower profile rubber.