Two old ladies : vintage machines

Introducing two of the three antic sewing machines that I have been itching to clean and bring back to life. Today is only the first day of this adventure. 

I love my house so much partly because the attics are amazing and contains treasures from the past. It used to be a Blanchisserie so some of these treasures are sewing related, including three old sewing machines.
These two are very interesting because they are from different manufacturer, but they are extremely similar. I know nothing about mechanic machines, so for now we will simply show both machines side to side. Next I plan to do an information research online, more cleaning, probably greasing and experimenting.

No 1 is an Helvetia (77G?) model. It has a numbered plate #179870. 
The presser foot installed on it is a Simanco 45321 which is used on Singer machines. I cannot seem to fit the other feet on the machine but maybe the settings were changed to accommodate the hinged foot?
No 2 is a Mundlos 88 model. #3513346
A piece is broken, with a number 2028 on it, and another piece close to the place it was situated has 2048. I believe it may be have been to add motorisation.
On top of this post you see their cover. Helvetia has lost both her key and her handle. Mundlos is in a slightly better shape. Here is their insides:

Front

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Backs

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Insides :

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Close-ups of the inside

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Accessories found in the drawer

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Details of the woodwork

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My first impression is that the Mundlos is a knockout of the Helvetia but of course this needs more investigation. Having both machines is great, as comparing the two will hopefully give hints to what works how, what may be missing etc.

Preparing this post has already taken a long time so I won’t translate it right no, nor will I write more of my impressions today. I hope you will enjoy the photos and maybe share your knowledge, hypothesis and questions. I am certainly looking forward to read your thoughts.

ETA: I found interesting info about the Mundlos here: https://www.fiddlebase.com/german-machines/mundlos/klasse-88/ and added the 88 model number (which was staring at me from the ornamentation of the machine!)
ETA 2: added Helvetia model, based on the bottom cast iron plate. And infos about the presser foot. Added number infos about two pieces of the Mundlos. And later found and added the production number for the Mundlos.