Land sounds like an anglicisation of another name, or possibly a variation on a patronymic name. There is however, the surname Landa which can be found in Suwalki area. This may be your best bet.
Compared with other areas, there are not many records for BMD in Suwalki generally or the Vilkaviskis area, as this area was the front line in both WW1 and WW2, and so many records were destroyed in wartime.
Do you not have a surname on these men's naturalization records?
Jill Whitehead, Surrey, UK
(All my ancestors came from this area).