Upvote:1
Will there be any consequence regarding the 90/180-day rule and overlapping time between these two visas?
No, time spent on the soil of the issuing country of a D visa doesn't count towards the 90/180 clock
Granting a visa is subject to the condition that the person in question leaves the Schengen area before the visa expires. This is why a visa cannot be granted to anyone who intends to enter Finland in order to apply for a residence permit or wait for a decision on a residence permit. This also applies to family members of Finnish citizens.
Excluding lying by omission (which can turn out pretty badly), if you give that plan to a Finnish visa official, you are pretty sure you will be denied, like stated in the text, thay will not accept someone who doesn't intend to leave the Area before the 90 days expire.
Nothing, other than an actual visa, can tell the Finnish official that you will actually be issued a visa by Estonia. In that situation nothing would prevent you being refused one/not applying at all and switching to become an illegal immigrant
Even to be granted a visa to Finland you will need that Estonian visa as a way to prove why you will not leave the Area after the visa expires
TL;DR : Get your Estonian visa and then apply for your Finnish visa using the Estonian visa and the appropriate documentation to prove that you are legally allowed to stay further than 90 days in Estonia