Are you problematic because your place is quite small and there are so many ideas running in your mind for the holiday decorations? Yes, this can be a bit of a problem. However, if you hire an expert, this should be resolved.
Yes and there are now so many skilled people you can hire in which one of the best can be found here https://holidaydecoratingnj.com/. You should check this out:
What are the common mistakes in decorating a small place?
It will be hard to deal with the blending of colors. If you will use a lot of colors which is usually the case when it comes to Christmas decors, chances are your place will look like a warzone small as it is. This is why you should just focus on using two to three color schemes. Yes, you can of course use other colors but they should just be minimal.
Skipping the lights just because your place is already crowded is also a mistake. The lights will usually complete the entire setup. However, you should not be too flashy because of your limited space. Just use soft white twinkling lights so the effect will just be subtle.
Not using a tree is not a good idea as well. The thing is there are different types of Christmas trees. If you are resourceful, you should be able to find something that will fit with the limited space you have. You can also keep those regular decors for awhile so the holiday decors will have a space.
The thing when you are decorating is aesthetics should be a part of the goal. You don’t only use holiday decors for the sake of the event. You also want to make sure your place will still look homely and great.