Will the team be placed in Tier 3, in the case where the team attempts to place the Loading Assembly on their bridge (Section 5, II, c&d, 1) and the bridge undergoes some sort of breakage--rendering the bridge unable to hold the Loading Assembly, ...

Yes, any Bridge that cannot hold the minimum load of 6.c Loading Assembly will be placed in Tier 3 as defined in 7.e.iii. Mass of the Loading Assembly is defined in 6.c.v. and may not exceed 1.5Kg.