Hi Paula,
Congratulations on your 45lb weight loss!
As far as modifications for the weight series, you should be fine by just using weights that are comfortable for you and building slowly. There are several ways to use the videos you mentioned, you may want to browse through the various rotations at fitnessvideofanatics.com for rotations that might interest you.
I liked teaming MIS and PH together on rotations, also BodyMax with either MIS or PH, but I generally do the strength oriented workouts like S&H and PS by themselves in a rotation. But that's just me!
But check out the site above, there are tons of rotations there, and you'll find some here as well.
Most modifications for Cathe will probably be for her cardio. BodyMax cardio is very fast and there is considerable impact, but it's do-able, and what I did when the impact or pace tired me out I'd just do regular up, up, down, down step until I caught my breath and was ready to resume with Cathe. Any and all plyo moves can be modified by just taking the jump out of them, and/or not squatting too deeply. Air born moves can be modified by remaining stationary, do the arm movements, but not the actual jumps. Or do as many jumps as you can and stop when winded, and do the remaining portions grounded. If you find you have any particular moves that are difficult, just post back and there are so many of us here that have found different modifications for every workout, so there will be an answer!
Donna
Fitness~ It's a journey, not a race!