Hello Samir,
I’ll try to give you a hint. If you need more precise information, I can help after work.
As for address cleaning, you can follow this workflow address Data Standardization - #5 by bruno29a. I recommend using Here API, you have more free requests and it’s more precise. The API call should automatically try to translate the input (messy) into an ordered output. If it’s not working, we can think about another way to do it.
As for computing the distance between each address and its nearest geocode, follow these steps. Firsts, take a point belonging to a geocode (eg the centre). Then, using the Cross Joiner node, calculate each possible combination between each address and each geocode. Third, refer to this post calculate distance between two latitude longitude points - #3 by danielesser to calculate the distance between each address and each geofence. Sort results so that for each address, you get the geofence with the smallest distance first (Sorter node). At last, use a GroupBy node to select the first result for each geocode (Group: addresses, Manual Aggregation: geocode, show first).
Hope it helps. Let me know if you need further information. 
RB