Is it bad to feed ur plants couple hours before lights out?

It does not matter when you feed your plants, the plants will only access what they need, when they need it.

It's worse to let your plants go far too dry than to water at less optimal times. Especially if you have tendency for RH to climb lights off you want to avoid watering/feeding right before they go off, and plants do utilise it the best in the first hours of lights going on, but in the end it's better to just do it whenever you can rather than waiting until the next day. If the time your lights go on is inconvenient (you're always at work etc), I'd consider just timing it more to your daily rhythm. Mine for example go on at 4PM so I aim to feed before 8PM. So - if you can in the first hours of light is better, but if the option is to postpone further just rather do it anyway even if they're about to go off. It doesn't make a huge difference as long as your environment doesn't suffer from it.

If you are in vegetative stage - 24 hours, no difference. In flower i would not worry till end of week 3. Later would give as much day time as i can. Overdrying when you have colas, can be same damaging as overwatering. In both ways rot gets boost start . Plants as people, will drink/eat most few hours after lights on aka having big breakfast ;)

No. Just be careful with the amount ect...

Its not advisable to water a dra hours before the light goes out.