Need Some Guidance ASAP

Hey Daniel, are you specifically going to be in Anaheim for those 2 days? If so, & this is your first trip to the Disneyland resort, you should do both!

Trying to cram in both with a park hopper for a first time visitor will be tough (especially with Carsland at DCA)

In terms of the walk of fame, that's one tourist "attraction" that's super polarizing. Many people hate it & are super disappointed, others embrace the goofy/cheesy factor & enjoy themselves.

If you choose to do it, you'd want to partner it with something else. Like a studio tour (WB, Paramount), Universal Studios / CityWalk, Farmers Market / Beverly Hills, Griffith Park / Observatory, Venice Beach / Santa Monica, etc.

Basically take advantage of being in LA & double or triple up on activities (because the walk of fame itself will not take you long at all)

Unfortunately, you are visiting during the first weekend of Spring Break, so the parks are going to be packed. Since you don't have a full day on Sunday and SFMM is closed on Friday, this is going to force you to do Disneyland on Friday and SFMM on Saturday.

For Disneyland, I would recommend only visiting Disneyland and skipping Disney California Adventure Park unless you: 1. Only care about the headliners and 2. Will not likely be returning for at least 5 years. Disneyland park itself has enough to fill two days, especially for first time visitors, and DCA is a full day park if you've never been.

Assuming you're only doing Disneyland, I would recommend doing Big Thunder Mountain Railroad first as it will be reopening after a 16 month refurbishment next week and will likely be very popular for a while. After that, head to Tomorrowland and grab a Fastpass for either Star Tours or Space Mountain, ride the other, then do Indiana Jones and Jungle Cruise while waiting for your return time. After using your Fastpass, ride Pirates of the Caribbean and Haunted Mansion (order doesn't matter), followed by Splash Mountain, and then just go from there in whatever order you feel like. Note that while Matterhorn Bobsleds does not have Fastpass, it does have a single rider line that will save you a ton of time (it is rarely longer than 10 minutes).

If you do decide to do both parks, I would recommend a somewhat different plan. Grab a Big Thunder Mountain Railroad Fastpass first thing in the morning, then ride Indiana Jones Adventure, Splash Mountain, Haunted Mansion, Pirates of the Caribbean (in that order). By now, your return time should be valid, so use your Fastpass, head to Tomorrowland for Space Mountain and Star Tours (Fastpass one while you wait for the other), then once you finish both head to DCA. Grab a Soarin' Fastpass, a World of Color Showpass (if you want to see the show), and a California Screamin' Fastpass (trust me, it will work), then ride Toy Story Midway Mania. By the time you get off, your California Screamin' Fastpass will be good, so use it. Ride Radiator Springs Racers (single rider recommended), then get a Twilight Zone Tower of Terror Fastpass (when you can), and do whatever until you've used both it and the Soarin' Fastpass. At this point, decide whether you want to spend the rest of your day in DCA or Disneyland and go to the appropriate park (returning to DCA 30 minutes before your World of Color showtime if you are seeing it).

For Six Flags Magic Mountain, I strongly recommend investing in a Flash Pass (at least Regular, preferably Gold). You will not get on all 18 coasters without it, especially since it will be the opening day for Colossus Backward and Batman Backward. Do not buy the pass until you actually get to the park, and either way ride Full Throttle before picking up the pass as it is not included. With a Flash Pass, X2 will be the only coaster that you're forced to wait in a long line for. Without it, I recommend going counter-clockwise around the park after Full Throttle, stopping at each major coaster as you reach it (skip Gold Rusher, Ninja, and Green Lantern if lines exceed 30 minutes, and do Superman & Ninja following Tatsu). If you are getting close to closing (say an hour or so before close) and have not yet reached X2, go there next. Don't bother with any of the non-coaster rides at SFMM except Lex Luthor, as they are all generic carnival rides. Also, be sure you get to SFMM 45 minutes before opening if you want any shot at beating the crowds.

Walk of Fame would be good to do on Sunday since you only have a half day and the attraction takes about an hour or so...definitely not more than two. If you have more time, pick something else to do in the Hollywood area as well.