FYI - the IKEA set will not work with Thomas trains. The engines are too tall for the tunnels, although the tracks will work. I know this for a fact because my son had an engine with him on our trip to IKEA the other day. I'm pretty sure that means it won't work with Brio, since the Brio items I have are sized the same as my Thomas stuff.
I have all Thomas, but mine is older because I got it from my now-teenaged nephew. Before I got into it, I looked at Whittle Shoreline, but it was way too expensive for us to buy, and I find Thomas stuff all the time in free bins at garage sales or very inexpensively at thrift stores, Ebay, garage sales. I understand not wanting your child to get into labels, but for serious train fanatics, it seems like having more engines/cars is more important than having a few really nice ones. We have something ridiculous like 31 engines/cars and about a 100 pieces of track, and I haven't spent more than $50 for all of it. My son loves to make up scenes from the books or from our trips to the local historical park, so we also have collected some bridges, tunnels and destinations that help. He's REALLY into trains (it's a family affair - his Papou builds model layouts), so I've gotten good at finding deals on them, and Thomas is so darn popular that you can get it cheap or free!
Instead of gluing down the tracks, you can buy Suretrack
and staple that to the board and clip the tracks in. We made our layout, marked where the clips should go, stapled them down and pressed in the tracks. When he's ready to change layouts, we pull up the tracks, and remove the stapled down clips. This way our track doesn't get damaged and can be reused.