To answer your question about why people give baby rice when it has little or no nutritional benefit - I have always assumed that it is just to get the baby used to eating from a spoon, and to the different texture of food - like a practice food, but one that is bland and soft, so is unlikely to cause the baby any problems.
My babies are all grown up now - 21, 23 and nearly 25 (god I must be old), and when they were babies, the NHS guidelines were to wean at 4 months, not six, as it is now, and all three were weaned on baby rice initially, and then onto other purees - banana is a good one, because it is really easy to make, but I used to puree all sorts of things - especially with my eldest, when I was really keen - I used to make all sorts of things and freeze them in cubes, so I could defrost a variety of different things for him to try. With the other two, I was busier and had less energy and motivation, so I tended to puree whatever I was cooking for the family, though I did make sure it was suitable, of course.
And please don't worry about asking questions - I think there is a saying that the only daft questions are the ones you don't ask - we were all new to this at one time or another, and I really remember what a huge responsibility it all is, and how much you worry about things that, in retrospect, were probably not worth worrying about.
Enjoy this lovely time with your little baby - you have got so many lovely things ahead of you - so many firsts to look forward to and enjoy - and even when there are tough parts (and dealing with this reflux must be so tough for you as well as for the baby), I always found that the good parts outweighed them, in the long run. Even the grumpy, Lynx-drenched, hormonal teenage years!
Before you know where you are, that little baby will be taller than you, and will be patting you on the head if you ask him to reach something down from a high shelf for you - or maybe that's just my lovely boys! They buy me gin, though, so all patronising head patting is forgiven! 