I have been using this combo in my team, and it simply wrecks. However, I have a few changes;
- On Groudon, you want 252 HP/252 Def/4 Speed, Impish in order to take on Extremekiller.
- Stealth Rock > Thunder Wave on Groudon
- Palkia should really be Scarf in order to revenge stuff easily, and in order to take on Scarf Kyogre better which is the #1 threat to this combination
- On Ho-oh, is Regenerator even released?
- Ho-oh should really be Substitute + Roost, best Ho-oh out there. 248 HP/252 Attack/8 Speed should suffice.
Ho-oh <3
The thing is, Ho-oh is a big part of that core, and not having Regenerator in Wifi really hurts it [Yea, Regenerator isn't released], also with life orb, you're losing health even faster. Stealth Rocks is everywhere, and with giratina being so common you're going to have a very difficult time removing them. You could use xatu/espeon in a attempt to keep stealth rock off, but you'd have to out-predict your opponent, and dialga/t-tar still beat xatu & espeon 1 on 1, so you even then you still aren't keeping sr off the field.
I'm not saying that Ho-oh doesnt work in wifi, just saying you'd need the right predicting skills + the right support in order to use to it's full potential.