Question about small gerbil behavior

Hi forum!

I just have a question regarding our new baby gerbil.

Last month, one of our gerbils, Mia, passed away :(

She was in the enclosure with another 1 year burmese gerbil, Canela.

So, to avoid Canela get depressed, we have now a 3 months new red-eyes white gerbil, she is Allie :) We are following the guide for bonding gerbils (Timon-Pumba guide :P ).

After 1 and half week with divider, we dont see any agression signs for now.

The only thing we notice with small gerbil, is when we put our hand close to the gerbil, she gives it small bites or also pees on it! Is that a good sign or could be dangerous when bonding? They are in heat time now, that's the reason they are back with back :P

What do you suggest? Thanks in advance! Regards from Argentina!