The many ways illegal immigrants can influence election outcomes in the U.S. including the presidential election

Here are just two quick examples:

1. The U.S. Census does not require anymore to answer the citizenship question. This would allow states gain more seats in the U.S. Congress and would reshape election districts etc.
2. Some municipalities allow illegal immigrants to vote locally. Will anybody verify whether these voters will not then go on to vote in statewide or federal elections etc.?