hi, nice to meet u. the amulet u get is like
1) Somdej + king rama 5 at behind
2) LP Koon wat banrai
3) LP Thuad
4) Phra Khunpean
5) Buddha, it look like Phra Pairee Pinas to mee.
and for ur question.
1) either is yes or no also can. up to the personal. if u lazy u no need any chanting also tak apa. if u rajin u can chant one. this is better. normally u can chant namotasha bagawato arahang sama samputho X5 times. this is most universal. if u wan add on extra khata also can.

2) if the amulet has been join the chanting ceremony properly before this. u no need reblessing one. bcos after the chanting/blessing ceremony the power is permanent stay there.  amulet power is not like hand phone bo, but battery, will go flat over times. see Somdej Toh amulet, chant by Somdej Toh himself over 100 year ago but the power in the amulet still there.  same like khunpean wat bangklang, aged over 400++, but the power is still there also. but if u dint confident with the current one, u can bring to monk to reblessing, reblessing is nothing wrong also. 

3) about the kemenyan asap will power up the amulet or not this one also depanding on personal though. some say yes, some say no.
if u ask me, i will say yes. but not only asap asap only, u also need chant the khata la to add on the power up.