@pat000, Sorry but far as I know you can't make 'pickups' with Menyoo (you can bet I tried!)
So, if you want a weapon you'll have to go to the 'weapons menu' and select it from there. You'll also add components from there too. On the real, 'Simple Trainer' is easier for that and you can still save the 'loadout' in Menyoo just fine.
Yes, you can select spawned peds disposition towards you. 'Easiest' thing is to go into the selected Ped's main menu and go down to the 'Task/Sequence' menu (I'm pretty sure that's the name.) In there you can select from a long list of actions your ped can do. 'Fight Ped' is the one you want. You'll need to select yourself as the ped it's supposed to fight and put in how long they're supposed to do so. If you want them to come after you, make sure you check the 'continue after time' box (I think that's the name of it. It's the only check box so you can't miss it.)
Be advised: you'll need to add a shitload of hit points to the ped before starting if you want the fight/chase to be worth doing. Don't make them 'invincible' unless you plan on eventually getting your ass kicked! Also, eventually if you get too far out of their detection area (you can set that range too) you'll break the sequence. They may reactivate if you get close or hit them (or not.)
There's another selection where you can have the ped 'Fight all enemies if provoked'. I find that only works with the 3 main characters or other game peds. MP peds don't react when you set that, but they work well with 'fight peds'. Lastly, you can use the 'enemy' selection and it 'works' but eh....