The B2-HA Heavy Weapon upgrade is expendable and has the cycle rule (At the end of your activation, if you did not use this card, ready it).

Does this apply specifically to the weapon in question, or the mini. To clarify, if I use the heavy weapon to form the attack pool, can the model contribute the normal unit weapon to attacks on their next activation. If so, does the cycle rule kick in, or does the model have to forgo an activation for that turn for cycle to refresh the weapon?

Any clarification on this one ?

According to the latest Rules Reference:

Only using the weapon, keywords, or other card text on
an upgrade card counts as using that upgrade card. A mini
added by an upgrade card is free to attack using a weapon
printed on its unit card and still benefit from the cycle
keyword.