they mentioned that they could chose what items they could offer Neighborly Help to.
Yes, they can: by going into the city, allowing it to load, scrolling around the city (takes forever if their first choice is B and you're looking to see if the builder's hut has any unpolished builders), etc. If the main hall is under construction, it won't be available to be helped. In higher chapter cities, with hundreds of neighbors, the time required for all that is unsustainable for me (and I'm retired; no idea how people with jobs have the time!).
Helping from both the FS members and Notification windows in browser are the same as in the mobile app. All of these show MH available to help whether under construction or not, BH is only presented as an option if it is not already 'full' with help, and it presents the highest culture bldg that doesn't already have a polish. I consider that a win-win for me and the player I'm helping. They really need to bring this to the world map on browser, too.
For me, mobile has the advantage with the daily prize and visiting on the world map. App also has a better 'move mode' for rearranging your city. Browser has the advantage in manual fighting. So, I play browser usually and log in on my tablet if I want the daily prize and/or to visit neighbors on the world map that are not in my notifications. I don't do that for rearranging, since I'm old with uncoordinated fat fingers, lol!