Statistical analysis for a social science research paper

I need a well-described statistical test with results to support my
short research. Here is what my research is about.

I am using SPSS in comparing landlocked and coastal countries in
various economic/social indicators. I have collected the data and
entered it into SPSS. I have 4 continous variables in total (and of
course, 1 dichotomous variable: coastal/landlocked). The 4 continous
variables are:
-Annual % of growth rate of GDP
-Trade as a % of GDP
-Oil production (million tonnes)
-Percentage of paved roads of total roads

These four continuous variables also form 4 of my hypotheses:
i) Countries with landlocked status are associated with smaller amount
of trade as a percent of total GDP than coastal countries.

ii) Countries with landlocked status are on average associated with
lower per capita GDP (US$).

iii) Countries with good infrastructure (roads) will not be affected
by landlockedness problem.

iv) The more oil a country produces, the less it is affected by landlockedness.

Basically I need a statistical test to test these hypotheses. Here is
what you want to watch out for:
- I don\'t want simple t-Tests comparing two categories for each
continuous variable because \'mean\' doesn\'t tell me much considering
the complexity of the issue. (This is very important because I have
already hired two statistical \"experts\" who only provided me with
t-tests).
- Variables 3 and 4 (roads and oil) are CONTROL variables. In other
words, I expect hypothesis 1 and 2 to be true ONLY once hypothesis 3
and 4 (variables 3 and 4) are CONTROLLED for. Think of it this way: a
country like Switzerland is landlocked (so I expect it to have lower
GDP per capita and lower trade, HOWEVER it does not. But it has good
roads, therefore to obtain good results I need countries like
Switzerland to be controlled for).

I have the data in SPSS and I need you to explain which SPSS
statistical test would be the most appropriate. After that, I need you
to run the test and provide me with CLEAR resulting data and
interpretation which follows statistical guidelines.

Please respond with the type of SPSS test(s) that you would run and provide a reasoning why you would pick such test(s).