NEED HELP: Taming new Alexandrine and getting along with IRN

[Porkemon]

I recently got a new weaned Alexandrine and it is scared of people. How can I tame the alexandrine and not make my IRN jealous? Will the Alexandrine go through the bluffing stage even though he's already weaned?

And let's say if the taming process went really well, how do I get both my IRN and Alexandrine get along with one another? I wouldn't want one of them to feel jealous and betrayed when I'm interacting with the other!

And also, how do I make them feel more comfortable around things when we're going out? My IRN took off twice when I'm trying to let him get used to the environment as he was really scared of things just like the Alexandrine and it made going out really stressful even for me, I really want them to feel safe and comfortable when outdoors
I wanted to get harnesses for both of them but I can't convince my parents as they're really expensive here.

Sorry for my bad English, it's currently 2:18am here and I'm getting a little rusty

[Wolf]

To be safe don't take your birds outside except for in a cage or wearing a harness or you run the risk of losing them. The expense of the harness is worth its cost as long as you use it as you are not going to have your bird fly away if it gets scared.
The best way to prevent the jealousy is to work with your Alexandrine in a different room from the IRN. AS far as I know there is no bluffing stage for an Alexandrine.
There is no way to make a bird like another bird, all that you can do is introduce them slowly to each other and separate them at the first signs of aggression and keep doing this until they decide to get along. Even if they don't become friends, you can get them to where you can have them both out at the same time as long as you are there to supervise the time out.

[Pajarita]

I doubt the Alex is really weaned... if he is, he would be the first I ever heard of. Breeders tell you they are weaned but, even when they really are (which most of them are not), they tend to revert in a new home and require hand-feeding so, please, get yourself some formula and offer him a syringe twice a day as well as soft food served fresh twice a day, also.
Wolf is right, you should NEVER take birds outside without a harness. It's a heartache waiting to happen. And, if the bird is stressed out when you take it outside, don't do it! Stress is not good for birds.

As to whether they will get along or not... well, it's anybody's guess as it depends entirely on them but they are both psittaculas and that is in your favor on the one hand and against you on the other because, if they do bond with each other, they will not want you to interfere (psittaculas are hard birds to keep bonded to humans).