Male kitten intimidating male cat

Willow (the cat in my kitchen) has been here for almost two weeks now - we have been having regular meetings recently and 'accidentally' leaving the kitchen door open as part of the introductions.

The thing is, Willow will hiss, growl and swat at Tibby (obviously, I stop this before it actaully happens), yet will do nothing towards Molly. Tibby seems quite intimidated by Willow and vice versa. Molly and Willow will just look at eachother and make a little peep style meow!

EDIT: However, having said this, when Tibby and Willow are in the same room, Tibby is quite content to sleep while Willow plays - there will be no problems at all Tibby will watch and then fall back to sleep....

I was wondering if this has anything to do with:

Molly's size - she's 2 years old and smaller than the six month old kitten?

The fact that Willow isn't neutered and Tibby is?

Do you think that if I get Willow neutered, this will ease the tension between them?!

I'm worried about the progress of the introductions and would be very grateful for any advice I can get on this!

Thank you in advance!

Sarah, neutering will help a great deal. But I would not interfere with the growling, swatting and hissing (perfectly normal for cats to do this) Now, if they were going airborn, stalking or rolling together, I would interfere, but let them figure it out for themselves, because every time you stop their process, that just means they have to start all over. No bloodshed? No worries-

Thank you, MA! I really appreciate your advice and support!

I do let the growls happen, but when Willow goes for Tibby, it worries me! Should I just try to let this go?!

Things will ease with the neuter? Why does that cause problems, is it the scents?!

What should I do when Tibby backs down? I'm worried that he's feeling put out - but i'mm making sure that he gets his 'my' time!

There hasn't been any bloodshed, so that's good! Plus Molly and Tibby are still their usual selves with eachother!

Why is it that Willow is happy with Molly and vice versa?!