As far as I knew 6 month old were supposed to be at 2 meals a day MAXIMUM
People who do BLW (finger foods rather than puree) might offer more than 2 meals in a day at this age, it really depends on what LO is ready for and interested in. The meals are not huge though, might be tastes alongside the family meals at the regular times, breakfast, lunch, dinner. Mine was very interested in solids and we moved to 3 meals per day rapidly but at no loss to milk intake and certainly not in an attempt to gain weight or risk reduced milk feeds.
I didn't give solids before milk, ever. IMO this route is only advisable if your LO is approaching 12 months and not taking much in the way of solids, not something to be done at only 6 months!
I formula fed but the feed times were similar, 7, 11, 3, 6.30 and a DF.
If anything I would more likely skip the rice cereal as the rice isn't adding anything to diet and agree with Erin that solids can cause her to take less milk which is the more important food right now. If weight is an issue I'd cut the solids right back and increase milk feeds.
Did your LO have an illness and go off food for a little while at any point? This can be the cause of a bit of weight 'loss' (not exactly loss but not gaining quite as much as might be expected) and they can take some time to get it back on again.