What happens if we leave the film in developer more then suggested times?
That's the same as if you push B&W film. You get higher contrast and more grain.
No, bleach, fixer, wash and stabilizer are all bathes which run to completion. You can underbleach/fix/wash/stab, but not really overdo these.
Can we expose film to light after bleach?
Yes, but not too much. Too much light would print out silver, which the fixer could then not remove unless you rebleach. If you are just curious to look at bleached film, the safest bet is that you inspect the film at leisure for any amount of time, then rebleach and continue the process.
Does it matter if bath times are long?
See above, you can only overdo the color developer step, all other steps can be done as long as you see fit with no risk to your images.
is it okay if i give it bath after every step?
If you mean with "give it a bath" that you give it a proper wash, it is not only ok, but absolutely recommended. Only the wash between CD and bleach is optional.
Can bath be followed by stabilizer?
The stabilizer should be the absolutely last process liquid which touches your film. In your case the correct process sequence would be CD, (optional) wash, bleach, wash, fix, wash, wash, wash, wash, wash, wash, stabilize.
If i were to push process Kodak Porta 400 shot at 800? how would i do that in c41?
By running CD for 3:45 instead of 3:15, everything else the same. The same warnings and limitations as with pushed B&W film apply.