Hi there. Hope you're doing better. I know how frustrating it can be to get contradicting infos. I think you'll have to eval the benefits here. Lets work through this.
If all is well, I also don't see a need to start solids earlier than 6 months. Rice cereal is usually introduced for its added iron, but your baby's iron level does not drop excessively until after 6 months. Your LO's digestive system may not be fully ready for solids. However, since your LO has reflux issue, adding solids would help a great deal. The reflux is caused by the upper sphincter not being fully function. It does not close fully as in adults and will not until about age 1. If your DS's diet is milk only, when he lays down, the milk will back flow through the slightly opened sphincter. If he has some solids, resulting in a thicker mixture, he will have less back flow through the sphincter. I think since your DS has reflux issue, the benefit for starting solids early may outweight waiting.
With that being said. Since he is yonger than 6 months, you may want to easy him into solids. First of all, let me confirm that rice cereal does cause gas. My LO woke up every 2 hours the two nights we tried rice cereal. She slept through the night again once we switched to oatmeal. Also, it may be easier for your DS if you feed the oatmeal with a spoon. Feeding through a bottle may cause him to choke or inhale some particles. If you do prefer bottles, make sure that the nipple has a big enough opening for thick fluid.
To start solids, cereal would be a good first food, followed by stage 1 baby food.
Day 1: 1 tblsp cereal with 4 tblsp of milk for the mid morning feeding
Day 2: 2 tabsp C with 8 tblsp M for mid morning
Day 3: 3 tabsp C with 12 tblsp M for mid morning
Day 4 and beyond: 3 tabsp of cereal with decrease milk for a consistency your DS prefers.
Have cereal in the mid morning feeding for 1 week, then increase the cereal feeding to twice a day. Once in mid morning and once in mid afternoon.
After the second week you could start other stage 1 food. Try 1/4 jar the 1st day, 1/4 the second day, and 1/2 for the 3rd day. Try each flavor for 5 days before moving to a new flavor, so that it easier to keep track of what you fed should your DS have allergic reaction. Always try new flavor in the mid morning feeding. Once you've tried a flavor, you could move it to the afternoon feeding.
This is a start, hope it'll help you.