IO standards question

hi,

I'm using a Startix IV FPGA (EP4SGX180FF) and I have 3 questions regarding IO standards, for PLL input and output pins, and for regular IO's:

1. what IO standards does the refclk inputs accept (for example "clk0n" and "clkop" pins)?

for example: does it support LVDS input, even if I set the VCCIO of that bank to 1.8V (for using it's IO's as LVCMOS-1.8)? same question if I set VCCIO=3.3V.

2. same question for the dedicated clock output pins at relevant banks, marked as "clkout0p" and "clkout0n" for example.

3. I use one bank as SSTL-1.5 satndard (for DDR3), with VCCIO=1.5V, VCCPD=2.5V and VREF=0.75V.

is it possible to use IO's from this bank as LVCMOS 1.5V input/output?

can I mix voltage referenced (SSTL) and non voltage referenced (LVCMOS) standards on same bank the same time?

thank you!