際に/際/際は => occasion, time N2
なくて済む/ないで済む => get by without doing ~ N2
を[経「へ」]て => After A N1
Time, Situation
に先立って => before; prior to ~ N2
に[先立「さきだ」]って/に[先立「さきだ」]ち/に[先立「さきだ」]つ => Before A occurs/takes place N2
Time, Situation
[際「さい」]して/に([際「さい」]し)/に[際「さい」]しての => At the time of A (which starts now).. N2
Time, Situation
~をたて(~を経て)      => through; after; via N1
ずに済む => get by without doing ~ N2
て済む => sufficient by; no problem to; resolve by ~ N3
に際して => on the occasion of; at the time of ~ N2