Hi,
Nice team, couple of things. You could try running a spread of 56 HP / 252 SAtk / 200 Spd Modest on Ninetales to outspeed Mamoswine and make him a lesser threat. At the expense of a little bulk, you practically removed a major threat to your entire team if played correctly.
Secondly, HP Ice seems to be a great option on Lilligant to alleviate your Landorus issues. EB Landorus or even LO Landorus are without a doubt a major pain for this team, and even someone with zero prediction can trouble this team when coupled with Tyranitar or the likes. It does lose a bit of coverage against things like Skarmory, Scizor (Steels in general) but Sun teams face very little trouble dispatching of those. Apart from that this is a stellar team and congrats on that.
Tales suggestion can be productive, thanks.
On the other hand, hp ice is a gamble; you check some things and get new weaknesses. EB and LO landorus aren't really why I'd considerate to switch to hp ice, BUT dragons; anyway, if sun is up EB landorus can be beaten by lilly; it it's not then it gets trickier, but she can get the job done as none of its unboosted attacks (bar crit-hits of course -.-) koes her, thus getting a chance to setup OR sleep an opposing poke, providing the given landorus decides to u-turn out (which is most likely). So it's not like she doesn't stand a chance, and even if working in tandem with t-tar, I doubt he wants to get asleep if tales is still roaming around. Now, with hp fire, on the same scenario, lilly could grab a sweep easier with hp, standing a chance to catch scizor on the switchin (because I doubt t-tar or any other grass neutral/weak mon wants to stay in to replenish lilly's health), getting past skarm and ferro, and so on.
Hp ice, on the other hand, doesn't really accomplish anything; if lilly's under sand landorus can escape and dent her in the same way as mentioned before, but she then gets walled and owned by scizor or any other steel poke (which are too common on landorus teams). And unboosted giga-drain does around 65% to standard landorus, maybe even more due to the -spdef nature most run (especially EB and LO), so with some prior damage lilly can easily finish him under sun without the need of hp ice.