Hi guys I just woke up at 8 am and before going out I want to start a series of question, starting a simple one.

1) Playing jambi, you are biting EC, a marines tries to deny but you kill him, after three or four times you notice it's always the same marine coming to defend EC a suply. After the exact moment you kill him, adding the spawn time and movement speed, how far in the map can this marine be when you reach supply? Can it be offload, pub, pub vent? And how fast exactly?

This kinda needs the speed specification for the marines/aliens. Is there such a table?

I have others question and will keep asking and answering.

//brb

This would completely depend upon how long it takes you to kill the EC extractor. A respawning marine takes about 15 seconds from the time you kill him while a full health extractor takes 30 seconds for a single skulk to kill. So if you kill him then attack the full health extractor, the marine will probably be approaching EC as you kill the RT, assuming he sprints the whole way.

Any scenario other than this depends on a whole host of factors, you'd likely need to be more specific.

As to speeds of each class, from memory:
Walking marine - 6
Sprinting marine - 7
Walking skulk - 6
Wallhopping skulk - 9-11
Gliding lerk - 11
Blinking Fade - ~16
Running Onos - 6.75

These are all easy enough to test for yourself, just open console in main menu and type the following:

and test all the lifeforms.

If I remember well you don't even need cheats 1 to have debugspeed.
You do need the cheats to change lifeforms though so I guess you're right.

debugspeed is a no cheat command and can always be used