With only 70 scrolls you can't do much. If you pull from the big treasures it is too random, and if you pull from the small treasures the really good ninja are the super rares and they cost 210 scrolls. Before you decide on a treasure, you should think about how long are you going to play the game. Are you going to play for 2-6 months? Then go for whichever treasure you want. Are you going to play for a year? Then maybe you should think about which super rare from the big treasure you want (p.s. gnw treasure rares are obviously the best if we don't consider breakthroughs).

Now about how to counter the LM meta. Well debuff removers are your best friends. Basically Han paired with poison and ignite works wonders. Wind main's sand dust or cheap event ninja like Chiriku or summer Hinata c*so be devastating for the LM since they normally don't run debuff removers.

If you want to pull in the GNW treasure you could run the Jinpachi-Kushimaru team with wind main and sand dust. You could try running a buffed up Edo Zabuza with edo Haku for barrier and Mangetsu/Fuguki, but since root also gives 100% resistance I'm not sure how effective this team will be.

Your other alternatives are to pull for Ay 3rd as you can play him with earth main, or go into kage treasure and hope for Mei for the Mei-Mabui-Tenten team (not so effective against root). Then again you need more than 70 scrolls for all these lineups...

You get ninja every 10 pulls too. Not sure buying seal scrolls is worth it when you can spend the same coupons to buy event ninja. If you really need scrolls get them from sun shop and monthly events, though imo getting power items from there is better.