Sri Lankan here!
1) Yes - your most recent itinerary makes sense (and I totally agree with the previous commentators about keeping daily road travel short).
2) It's a bit late, but re: your questions on Amanwella vs. Chena Huts - I've been to the former, and found the service there to be of a very high quality (despite the reviews on Tripadvisor saying that hotel does not meet Aman's legendary standards!).
I've not been to Chena Huts, but I have stayed at a couple of other properties by Uga resorts. Their hotels are also pretty good, although I did find their standard of service to be a bit variable between properties (from extremely high, in the Uga Residence in Colombo, to merely "pretty good" at Ulagalla, Anuradhapura).
A couple of close friends have stayed at Uga Jungle Beach; they described the service as being less polished than Ulagalla - although this again is a relative comment; any of the Uga properties are still better than most "5-star" hotels in Sri Lanka!