Hi,
Im a returning player to Battledawn and i've forgotten if you have units in your colony, but not in a squad, will they fight any incoming attacks and if they would be killed in a attack on the base.

Any units on your colony will defend you. Even if you have units recruiting and they finish the tick the enemy lands those will defend you as well. Just to be clear though if the attack is 3 eta and your units finish in 4 tick they will not defend you.

Yes they do

even units which are you training in base, suppose will be ready in 3 ticks, and attack is at ETA 3, those will also defend

but not those who have more ticks time than incoming

okay thank you, i guess the only way to save your units is to send them out and recall them after the attack so basically dodging the attack.

Right, that is also a good way to avoid spy attacks except in that case instead of returning to land after the attack you would return to land the same tick as the attack.