1.  Is this group open to autosomal DNA testers or mitochondrial testers or female testers?  Short answer is no.  The reason is that most Euro families are traced thru their paternal line which lends itself to only one test ...the male "Y" chromosome test ... thus, this is the test we use and we only test males 

2.  Does the administrator have any background success with using this test to find relatives "across the pond"?  Yes, a Swiss relative was found using yDNA testing in combo with paper genealogical research.  That study was noted for its success in German Life Magazine (See Ruple ydna Surname Group at ftdna.com)

3.  What percentage of this Tedder/Tudor yDNA surname group are US based?  So far, all but one.  However, we hardily encourage English/Welsh/Scottish Tedder, Teader, Tudor, Tuder males to test and provide us a brief outline of their family ancestry (a) to establish their own DNA haplotype and (b) to use that haplotype to compare with potential UK and USA genetic cousins.

4.  How many distinct haplogroups are there since not all group members have matching haplotypes or haplogroups ?  Five