A lot of the games that you named are not exactly "traditional" pinball machines that most people are looking for in a first. They make a good fourth or fifth game, but the first... not so much. Here are my thoughts, in no particular order.
Popeye - Mine is sitting about three feet to my left right now. I think it is the most amazingly designed machine ever made. The way they integrated the boat theme with the playfield is nothing short of genius... but it just doesn't play that great. A TON of the shots are hidden. I can overlook that since I have a bunch of machines, but as a single machine I definitely wouldn't keep it set up.
Fire - It doesn't have pop bumpers, and being the fancy edition of Fire it's an expensive system 11 for more than most system 11 games sell for. The lack of pops drives some people mad. The gameplay on it is also pretty darn simple, even for a system 11. Again, it's a great game if you have like five and want something totally different, but I can't imagine it being good for one.
Riverboat Gambler - It's been a LONG time since I've played it, but it has a betting theme where you actually bet stuff using buttons on the front or lockdown bar or something, and again it's unique and usually not what people want for their first machine. Another great "mix up the collection" title.
Medusa - It's a relatively simple game from the early 80s that is unique in the fact they more or less crammed two half playfields into one. Like a theme that I keep repeating, it's a neat machine in a collection of five or so, but it's not the type of pinball machine most people think of when they hear you have a pinball machine.
Austin Powers - I saved this one for last because of these options, I think it is far and away the best of the bunch. AP is a great playfield layout (anyone who disagrees, go look at the bunches of people who love Iron Man - AP is Iron Man with more stuff on the playfield). It has pop bumpers. It has multi-ball. It's a DMD machine. The only problem with AP is once you get good at it, you can really keep the ball in play for a long, long, LONG time. Unlike a lot of games, it doesn't seem to me to matter how nasty you set it up, I seem to be able to play any one of them for 20 minutes a game, which drives me nuts - I like 3 minute games. If you want a longer game, this is a very good first choice, I think.
Austin Powers, Popeye and Fire would be the easiest three to sell down the line.
Final thought - If your goal is just to play, ignore this. If you want to learn how to repair and stuff like that, you might want to start on the Medusa for a bit. When I started in this crazy hobby many, many moons ago, I bought mid 80s, single level Bally game as a project, and I spent about 6 months just repairing the thing, learning how to do it and so on. I graduated later to a system 11 (Space Station), and once that nightmare was done, I figured out how to repair just about anything. That is a really nice skill to have, and if that is your goal, I'd suggest that Medusa is going to be far less overwhelming to look at than any of those other games.
Good luck, hope this helped in some way