Heater core rebuild

Got started on my heater core rebuild and it is not going my way...  here's a few questions based on the picture below;

1) Should there be a seal where you see a gap on top of the plate holding the 2 tubes (I have the Zip heater core seal kit; which contains a lot of items; but it's not clear what goes where...).  On the right side; I'm showing one I was tempted to squeeze under the hold down plate.

2) The bracket (left) held by 1 screw that will hold the 2 pipes from moving does not fit between this new heater core I just bought; what's the best option; reshape the pipes or reshape the bracket?  I'm assuming the bracket; BUT as you can see, the 2 pipes don't quite site well on the left side, they sit a little on top.  Looks like one of the pipe should be rebent a little; but I'm not sure how to do this without damaging it.

3) On the 2nd picture; that rectangle metal clip; I broke one tab on the side.  I tried to glue the plate but it's not holding enough.  Anywhere I can find one of those?  Or any other idea on making it stay in place?

Thanks!