texaspsych

i ran into a traditional jj yellow belt at the gym and we worked on some stuff together. first time i got to experience it first hand. as far as i can tell, the submissions are all the same. bjj has alot more ground technique for positions and transitions and jjj has more standing submissions and throws

i don't know about aikido, but his judo will make hima good rival with throws and he'll have some ground work, but not much. have your bjj friends show you the basic positions to use on him when on the ground and have them show you the basic submission set ups. you'll probably pick that up fast since you already know the submissions. one of bjj's principles is "position before submission." basically, it's easy to submit a guy oncve you are holding him in place with your weight.

bjj didn't have leglocks until the UFC came along and we rolled with sambo guys. but now bjj borrows alot of their leglock setups. be careful with kneebars and heelhooks because they can permanently injure the leg if you apply them too quickly and powerfully or if some novice doesn't know to tap out.

i think royce gracie's book "ultimate fighting techniques" would be a very good aid for you. it covers all the basics extremely clearly. also, check out grapplearts.com they have some great techniques.