Congratulations on the new baby!
I don't know much about stones (is each one 11 or 13 pounds? I will google it - aha! 14 lbs/6.35 kilos). I do recall weighing myself in England and thinking I was so light!! The number is so small... similar with kilos. But then so hard to lose just ONE
ANYway - I never really used the ricotta. Cottage cheese and Greek yogurt (which was not available when I first did SBD in ~2007) have more protein. Hopefully you can find lowfat/nonfat versions of these if you want to try. I use the Greek Yogurt often as a dessert - with sweet flavorings, or nut butters, or no-sugar-added cocoa mix (<<that might be for Phase 2 though). I often use cottage cheese in place of ricotta in baking - like a zucchini and/or eggplant (aubergine) lasagna without noodles. I often whip it first to get rid of the curd texture. I also have it with fruit in Phase 2 (my favorite is orange or grapefruit segments with cinnamon).
YES nuts allowed in Phase 1, just keep to 1 serving/day (= 1 ounce/28 grams).
Lots of people here jump between phases - I often have Phase 1 days mixed in with Phase 2 and Phase 1.5 (the unofficial in-between phase that many people use, usually it means some fruit but no grains). But you should do a full 2 weeks of Phase 1 as soon as you are fully committed, as it really kicks the cravings and sets you up for longterm success. It also just feels good to accomplish that! I don't think anyone here will recommend staying on Phase 1 for a long time.
Good luck to you! I think that SBD is a wonderful healthy diet.