It's possible maybe but I don't think it's all that likely. And think of how big a chunk of tree they'd have to use if each quarter of that table was from a single piece of wood. Basically, fancy tables with patterns in the grain or different decorative edges or large spaces between seams are likely to be veneered. If it looks like someone could have glued a bunch of smaller boards together into a big board and then cut out a table, it's solid. But if there aren't many seams in the grain and it would have had to have come from a giant sequoia tree, odds are good that it's veneered. For solid wood, oak is usually a good bet. Veneered tables are technically still (usually, especially with older CL stuff) solid wood...just not the same wood all the way thorough. :) You should give veneer another try. Just sand gently and keep it out of the rain.

If you want to preserve every fraction of an inch of headroom, use engineered 3/8" ceramic underlayment plywood. It has more layers of wood and glue than standard plywood and is stiffer. Otherwise, standard 3/8" will not do much. I once used it instead of 5/8" and eventually all the grout lines cracked. FWIW, where I install tile or stone on 2"x10" @16" o.c. framing I have two layers of 5/8" or 3/4" plywood subfloor

Planning to buy a stain marker too from walmart, as I have gift card. Should I get dark walnut or red oak or red mahogany, leaning towards the red oak. Will also get the guardian wood repair filler sticks. http://www.walmart.com/ip/Guardsman-Wood-Repair-Filler-Sticks-with-Sharpener-5-count/21296155

"Some worked, some didn't." It happens. Unfortunately what happens in new construction is framers don't put enough pressure on where they're fastening, especially with the use of pneumatic nailers today. They may spread enough construction adhesive on the floor joists, but once the plywood is laid, they run like heck to nail it home. IE: the adhesive isn't squeezed down in any consistent matter, creating voids that cause squeaks. I learned this while working on a job ten years ago. It was actually a warranty claim. The builder was found at fault because the framers didn't install the ply the right way. Not many do really. To them it's about getting the job done. Most don't even think about problems it can cause. The customer naturally wanted it done right. Hence, all flooring and sub flooring was removed and re-installed. Ken Fisher