A shield slot is likely to require an illuminated god's book. Zamorak's book costs over 22 million one of the best options is armadyl's Law book which costs 1.7M: it's only got two less ranged offenses, however it has RS gold defensive capabilities, and when you've illuminated it you'll get a nice huge prayer reward.
Your cape is a must unless you're engaged in an activity that isn't going to be effective, like shooting ogres inside a cage. In this case, you must wear your best ardougne cloak or something with offensive/prayer bonuses. Red dragonhide, obviously is not recommended unless you wish to become empty. I hope that can help!
When I look at your charms, I'm not 100% sure that you'll be able to make 70 without having additional charms. If you're using golds and barker Toads, there's a need for 1840 gold charms at 160k xp. greens it's 1620 using Ibis and Crimsons. with the blues and other plants are likely to be the ones you need to keep, but it's 343 with the kyatt's and graahks.
Up front, that's about 1.5m from toads to 4.7m of ibis 2.5m for stranger plants along with 3.4m with regard to Graahks (4.4m for Kyatt). A mix would be somewhere between. If you're lucky, you'll get roughly half by sales of the pouches. However, there is one exception: blue pouches, which may earn your money back, but you'll have to find an appropriate source for blue charms.
I'm convinced you'll not able to afford less than 1m , and even more likely you'll be spending 1.5-2m for the next three levels. Summoning is one of the ones that bite your knuckles, and don't be too concerned about costs.
It's worthwhile to obtain these levels. Yip, Tort and Bat are all excellent familiars but I just don't know of a super-cheap method that doesn't require a huge sum of prep time. Abyssal Lurkers (Which requires you to farm abyssal animals yourself to get the abyssal appeals) and Graahks/Kyatt's being among the only familiars that are truly profitable and sellable I know of below 66.
I'm not searching for the most exp pouches, I would like to find pouches that can be sold to limit my losses as I have only 2 mill in my savings account, but want 69 summoning in the buy OSRS gold near future, and I'm planning to use as many charms as necessary, as I must.