It's impossible for me to get an idea of what you're eating and how hard you're actually pushing yourself.

If you can start logging your calories, that would help tremendously. I recommend using an app/website like Myfitnesspal.

If you don't know what your target calories is, I'd recommend using something that uses the Mifflin St.Jeor equation to calculate your BMR. If you google that, you'll come up with a Calorie Calculator that uses your Age, Sex, Height, and activity level to come up with how many calories you need to eat to remain your weight. If you're trying to gain muscle, the rule of thumb is eat 500 calories more than that.

If all you can afford is ramen noodles, I highly recommend avoiding using much of the flavoring as it has an insane amount of sodium in it.

At your level of training, you could do push-ups and squats on the same day without any difference. You're still missing out on training your back though. Add in pull ups or chin ups. If you over develop your chest and it's too strong for your back, your shoulders will roll forward more, your posture will decline, and you'll be in chronic pain.

How many days a week is going to require you figuring out what results you're having. If you can recover from 5 days a week then do 5. If you're halting in progression, do 3 because you're either not eating enough or not giving your body adequate recovery.

Yes a trampoline is good cardio.