Lol thanks guys <3
Since I main MK now I can actually help you guys with this
Go ahead and strike SV and BF, they are by MKs best neutrals along with some of his better stages in general. So save yourself the trouble and don't play here.
You want to take MK to Yoshi's since it's Lucario best neutral, or take him to FD since it's MKs "worst stage"
Yoshi's is also not that great for MK, but as most everyone knows, he doesn't really have a bad stage.
CPing him to Frigate isn't a bad idea, but it's also a good MK stage but if you know this stage like the back of your hand then use it. I also suggest banning RC against him for obvious reasons. There's not much Lucario can do on RC as you guys already know. But you'll end up either on Brinstar or on Delfino. So practice both of these stages. IMO Brinstar and Delfino are MKs best stages.
Let me go into more dept about Brinstar and Delfino. MK can shark you on both stages very easily. With the acid on Brinstar he can pin you be getting above you and using nado. So you're either taking a dip in the acid or being caught up in nado. Both are going to do the same amount in damage but nado will do less dmg more than not. The slants play into MKs forward and down smash very well, as do the gooie pillars and and gooie little ball things in the middle of the stage that break lol. Also since this stage has very tight side blast zones, shuttle loop kills are very tempting, easy, and safe (for the most part) to pull off. Since there's the acid and the plats on each side to catch MK, going for an easy up-b kill will happen and could ruin the whole match for you. With bad DI you can die at around 50%. Lol trust me on this one, it's a big reason why I CP Brinstar with MK.
Now as for Delfino. Like I said before, sharking is very easy on the main part of this stage. It's a very viable strat and one that will be abused here. Whenever the stage lands on different scenes the side blast zones become very tight like Brinstar, but actually they're even tighter, and since it's even safer than Brinstar since you can't fall to your death or damage after going for the shuttle kill because you'll either hit the ground or water, it will be exploited when given the chance. You will die very early too. I'm talking 30-40% if pretty close to the blast zones. Lol I've been one to do this many times so again I speak the truth
Halberd is another good stage for MK, along with Luigi's Mansion, but Lucario is also pretty good on Mansion.