The marked one in yellow turn it 180 degrees ( on X-Y axis) , the peak to be like the under one., and this movement to the others too.
180 on X, and after 180 on Y ? (rotation gizmo enabled, so it is easier to imagine axis)
X is going through red circle of gizmo
Y is going through yellow circle of gizmo
Z is going through blue circle of gizmo
Now looks good.Just on the blue ( Z ) was need it to be turn it.
test_001.blend (9.3 MB)
file saved in blender 2.80, if You want open it in 2.79, open file via 2.80, select objects of interest copy them by ctrl + c, open blender 2.79 and paste them via ctrl + v
Tomorrow i update my Blender to 2.8.My net connection is slow to do it now and i let you know about the test.
I deleted the forms to not be confused by them and now the shapes are all in GOOD DIRECTION ORIENTATED.
SHAPE TRIAL .blend (558.7 KB)
hehe i’m so greedy 
I should make this file available sooner for download XD it would save a few minutes…
…anyway what is next step
This shapes can be lofted or interpolated or other command which is better for this purpose and to be smooth and the WALL thickness of the tube to be 2 mm .
Here at the flange 2mm thick oval or rectangular :
------ in one end for the father form with a neck of 2 mm
------and at the mother side the flange thickness to be 4mm and the neck -2mm
------with 4 holes of 6 mm diameter each.
the way i did it, was that:
- Duplicate and convert every curve to mesh
- Join each column via ctrl + j
- Go to edit mode, use loop tools addon to space vertices
- Select first two loops join them via bridge tool from loop tools addon, select linear interpolation, and 3 or 4 segments
- repeat this operation for every pair of loops you want to bridge
- when mesh is redy, you can use subsurf modifier set at 2 to smooth it
One difference is that i used more segments on bridging stage that’s why mesh was not so smooth
- last loop can be extruded outwards in edit mode to create flange
- wall thickness can be added via solidify modifier
I will give a try to do it.
Yes ,like this i need to be .
Question: The loft between the shapes in this pictures is the final stage or can be better do it in blender, looks a little ugly .
I have now the 2.8 version too. Is totally different how looks like from the previous versions.
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You will get used to new blender real quick
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look of this shapes is dependent on how many segments in between profiles was used to bridge shape
this one o screenshot is 3 segments and subsurf modifier, also i used mat cap to better visualize curvature of mesh -
Have look at it on your computer, play with the settings tubes2_8.blend (2.6 MB)
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Can You somehow visualize your idea of final shapes ??
EDIT:
I forgot to mention shapes are scaled about to dimensions from earlier posts
EDIT 2:
In your the original post the ellipses were probably smaller than those in the file that I attached
In original post that was just a trail to learn how to join the 2 tubes together and after to do it how i detailed to you.
The shapes dimensions can remain like this.
If there are more segments between profiles is smoother and at printing too?
The middle tube now i see in 3d for the first time.I do it just with hands .
Are you thinking of the final shapes of the tubes?
Have you added some thickness to the tubes? 2 mm wall thickness is enough for the moment.
Is good now this version, is a combination of multiple 3d programs on which i try it to do this tubes. I can see how are the shapes along the tube when i zoom,like in 3d max. yummmi
When i put the View number higher then 3 ( 4,5,6 ) is crashing , i read about this possibilities for the beta version.
tubes2_8 _1.blend (6.9 MB)
less segments + subsurf modifier = smoother
more segments + subsurf modifier = more defined
Are shapes ok? just bad interpolation? or both shape and interpolation is bad ?
last row has thickness
Crash most likely is caused by RAM limit, do no subsurf every object on scene 
Yes , the shapes are OK. I just asking if the interpolation can be better or not, if not we live it like this.More stuffs will come out after printing, i hope if will be.file tubes2_8 _1.blend has 3 new rows of objects and they have a bit different interpolation, which one is best ?
just now opened, is a little slower my laptop or else. yes i see them .let me check them a little.
let say more segments + subsurf modifier = more defined
is big difference when you have it already in your hands this tube or else and when watching here them
i think my RAM is here the problem.