Google Sheets/Excel Formula for formatting addresses

Google Sheets Formula for Address Formatting

For cells:
C3: First Name 1
D3: Last Name 1
E3: First Name 2
F3: Last Name 2
H3: Mailing Address 1
I3: Mailing Address 2 (Optional)
J3: City
K3: State
(L3: Country unused)
M3: Zip

Name Formatting:
If firstname 2 doesn't exist:
Firstname1 Lastname1
If lastname 2 = lastname 1:
Firstname1 & Firstname2 Lastname1
If lastname 2 != lastname 1:
Firstname1 Lastname1 & Firstname2 Lastname2

Address Formatting:
Mailing Address 1
(if Address 2 exists): Mailing Address 2
City, State Zip

Formula:
=CONCATENATE(C3, if(D3=F3, " ", CONCATENATE(" ",D3, " ")), if(E3<>"", CONCATENATE("&", CONCATENATE(" ", E3), " ", F3), ""), CHAR(10), H3, CHAR(10), if(I3<>"", CONCATENATE(I3, CHAR(10)), ""), J3, " ", K3, " ", M3)