Here it means 'to gather' or 'to develop'. For example, " Mr. Hosokawa could not seem to develop any concern for Nansei". I.e. He wasn't concerned about Nansei.

This is a very odd expression. As far as I know, there is no such phrase as 'startle up'. Where does the sentence come from? To 'startle' means to surprise someone suddenly. If you are startled by something, you'd typically open your eyes wide and/or make a slight jumping movement. I have never heard anyone say 'startle up', and it doesn't make a lot of sense in this context. 'Stir up' might work, though. My guess is that this was not written by a native speaker and that the writer is using the wrong word. In fact, I just did a search for 'startle up', and the only result took me right back to this page, which is always a bad sign.